iff *r. ISO HANDBOOK OF MATHEMATICS FOR ENGINEERS % Qraw~3/ill Book (n. 7ne PUBLISHERS OF BOOKS F O R_^ Coal Age v Electric Railway Journal Electrical World * Engineering. News-Record American Machinist v The Contractor Engineering 8 Mining Journal ^ Power Metallurgical 6 Chemical Engineering Electrical Merchandising Handbook of Mathematics for Engineers BY EDWARD V. HUNTINGTON, PH. D. ASSOCIATE PROFESSOR OF MATHEMATICS, HARVARD UNIVERSITY WITH TABLES OF WEIGHTS AND MEASURES BY LOUIS A. FISCHER, B CHIEF OF DIVISION OF WEIGHTS AND U. 8. BUREAU OF STANDARDS ;. S. ^rrTT MEASURES, 4 REPRINT OF SECTIONS 1 AND 2 OF L. S. MARKS'S "MECHANICAL ENGINEERS' HANDBOOK" FIRST EDITION SECOND IMPRESSION McGRAW-HILL BOOK COMPANY, INC, 239 WEST 39TH STREET. NEW YORK LONDON: HILL PUBLISHING CO., LTD. 6 & 8 BOUVERIE ST., E.G. 1918 / c COPYRIGHT, 1918, BY THE McGRAW HILL BOOK COMPANY, INC. COPYRIGHT, 1916, BY EDWARD V. HUNTINGTON. TH M A F L 1C X> R IB H H YOKJC PA PREFACE This Handbook of Mathematics is designed to contain, in compact form, accurate statements of those facts and formulas of pure mathematics which are most likely to be useful to the worker in applied mathematics. It is not intended to take the place of the larger compendiums of pure mathematics on the one hand, or of the technical handbooks of engineering on the other hand; but in its own field it is thought to be more comprehensive than any other similar work in English. Many topics of an elementary character are presented in a form which permits of immediate utilization even by readers who have had no previous acquaintance with the subject; for example, the practical use of logarithms and logarithmic cross-section paper, and the elementary parts of the modern method of nomography (alignment charts), can be learned from this book without the necessity of consulting separate treatises. Other sections of the book to which special attention may be called are the chapter on the algebra of complex (or imaginary) quantities, the treat- ment of the catenary (with special tables), and the brief resume of the theory of vector analysis. The mathematical tables (including several which are not ordinarily found) are carried to four significant figures throughout, and no pains have been spared to make them as nearly self-explanatory as possible, even to the reader who makes only occasional use of such tables. For the Tables of Weights and Measures, which add greatly to its useful- ness, the book is indebted to Mr. Louis A. Fischer of the U. S. Bureau of Standards. All the matter included in the present volume was originally prepared for the Mechanical Engineers' Handbook (Lionel S. Marks, Editor-in-Chief), and was first printed in 1916, as Sections 1 and 2 of that Handbook. The author desires to express his indebtedness to Professor Marks, not only for indispensable advice as to the choice of the topics which would be most useful to engineers, but also for great assistance in many details of the presentation. All the misprints that have been detected have been corrected in the plates. Notification in regard to any further corrections, and any suggestions toward the improvement or possible enlargement of the book, will be cordially welcomed by the author or the publishers. E. V. H. CAMBRIDGE, MASS. April 29, 1918. M171600 CONTENTS Page PREFACE v SECTION 1. Mathematical Tables and Weights and Measures 1 (For detailed Table of Contents, see page 1.) SECTION 2. Mathematics: Arithmetic; Geometry and Mensuration; Algebra; Trigonometry; Analytical Geometry; Differential and Integral Calculus; Graphical Representation of Functions; Vector Analysis 87 (For detailed Table of Contents, see page 87.) INDEX . . 187 SECTION 1 MATHEMATICAL TABLES AND WEIGHTS AND MEASURES BY EDWARD V. HUNTINGTON, Ph. D., Associate Professor of Mathematics, Harvard University, Fellow Am. Acad. Arts and Sciences. LOUISA. FISCHER, B. S., Chief of Division of Weights and Measures, U. S. Bureau of Standards. CONTENTS MATHEMATICAL TABLES BY E. V. HUNTINGTON PAGE Squares of Numbers 2 Cubes of Numbers 8 Square Roots of Numbers 12 Cube Roots of Numbers 16 Three-halves Powers of Numbers. . . 22 Reciprocals of Numbers 24 Circles (Areas, Segments, etc.) . 28 Spheres (Volumes, Segments, etc.).. 36 Regular Polygons 39 Binomial Coefficients 39 Common Logarithms 40 Degrees and Radians 44 Trigonometric Functions 46 Exponentials 57 Hyperbolic (Napierian) Logarithms. 58 Hyperbolic Functions 60 Multiples of 0.4343 and 2.3026 62 Residuals and Probable Errors 63 Compound Interest and Annuities. 64 Decimal Equivalents 69 WEIGHTS AND MEASURES BY LOUIS A. FISCHER PAGE U. S. Customary Weights and Measures 70 Metric Weights and Measures 71 Systems of Units 72 Conversion Tables: Lengths 74 Areas 76 Volumes and Capacities 76 Velocities 78 Masses (Weights) 78 Pressures 79 Energy, Work, Heat 79 Power 81 Density 81 Heat Transmission and Con- duction 82 Values of Foreign Coins 82 Time - 83 Terrestrial Gravity 84 Specific Gravity and Density 84 MATHEMATICAL TABLES SQUARES OF N 1 2 3 4 5 6 7 8 9 ll 1.00 1.000 1.002 1.004 .006 1.008 1.010 1.012 1.014 1.016 1.018 2 1 1.020 1.022 1.024 .026 1.028 1.030 1.032 1.034 1.036 1.038 2 1.040 1.042 1.044 .047 1.049 1.051 1.053 1.055 1.057 1.059 3 1.061 1.063 1.065 .067 1.069 1.071 1.073 1.075 1.077 1.080 4 1.082 1.084 1.086 .088 1.090 1.092 1.094 1.096 1.098 1.100 1.05 1.102 1.105 1.107 .109 1.111 .113 1.115 1.117 .119 1.121 6 1.124 1.126 1.128 .130 1.132 .134 1.136 1.138 .141 1.143 7 1.145 1.147 1.149 .151 1.153 .156 1.158 1.160 .162 1.164 8 1.166 1.169 1.171 .173 1.175 .177 1.179 1.182 184 1.186 9 1.188 1.190 1.192 .195 1.197 .199 1.201 1.203 .206 1.208 1.10 1210 1.212 1.214 .217 1.219 1.221 1.223 1.225 .228 1.230 1 1.232 1.234 1.237 .239 1.241 1.243 1.245 1.248 .250 1.252 2 1.254 1.257 1.259 .261 1.263 1.266 1.268 1.270 .272 1.275 3 1.277 1.279 1.281 1.284 1.286 1.288 1.209 1.293 .295 1.297 4 1.300 1.302 1.304 1.306 1.309 1.311 1.313 1.316 .318 1.320 1.15 1.322 1.325 1.327 1.329 1.332 1.334 1.336 1.339 .341 1.343 6 1.346 1.348 1.350 1353 1.355 1.357 1.360 1.362 .364 1.367 7 1.369 1.371 1.374 1.376 1.378 1.381 1.383 1.385 .388 1.390 8 1.392 1.395 1.397 1.399 1.402 1.404 1.407 1.409 .411 1.414 9 1.416 1.418 1.421 1.423 1.426 1.428 1.430 1.433 .435 1.438 1.20 1.440 1.442 1.445 1.447 1.450 1.452 1.454 1.457 .459 1.462 1 1.464 1.467 1.469 1.471 1.474 1.476 1.479 1.481 .484 1.486 2 1.488 1.491 1.493 1.496 1.498 1.501 1.503 1.506 .508 1.510 3 1.513 1.515 1.518 1.520 1.523 1.525 1.528 1.530 .533 1.535 4 1.538 1.540 1.543 1.545 1.548 1.550 1.553 1.555 1.558 1.560 1.25 1.562 1.565 1.568 1.570 1.573 1.575 1.578 1.580 1.583 1585 3 6 1.588 1.590 1.593 1.595 1.598 1.600 1.603 1.605 1.608 1.610 7 1.613 1.615 1.618 1.621 1.623 .626 1.628 1.631 1.633 1.636 8 1.638 1.641 1.644 1.646 1.649 1.651 1.654 1.656 1.659 1.662 9 1.664 1.667 1.669 1.672 1.674 1.677 1.680 1.682 1.685 1.687 1.30 1.690 1.693 1.695 1.698 1.700 1.703 1.706 1.708 1.711 1.713 1 1.716 1.719 1.721 1.724 1.727 1.729 1.732 1.734 1.737 1.740 2 1.742 1.745 1.748 1.750 1.753 .756 1.758 1.761 1.764 1.766 3 1.769 1.772 1.774 1.777 1.780 1.782 1.785 1.788 1.790 1.793 4 1.796 1.798 1.801 1.804 1.806 1.809 1.812 1.814 1.817 1.820 1.35 1.822 1.825 1.828 1.831 1.833 1.836 1.839 1.841 1.844 1.847 6 1.850 1.852 1.855 1.858 1.860 1.863 1.866 1.869 1.871 1.874 7 1.877 1.880 1.882 1.885 1.888 1.891 1.893 1.896 1.899 1.902 8 1.904 1.907 1.910 1.913 1.915 1.918 1.921 1.924 1.927 1.929 9 1.932 1.935 1.938 1.940 1.943 1.946 1.949 1.952 1.954 1.957 1.40 1.960 1.963 1.966 1.968 1.971 1.974 1.977 1.980 1.982 1.985 1 1.988 1.991 1.994 1.997 1.999 2.002 2.005 2.008 2.011 2.014 2 2.016 2.019 2.022 2.025 2.028 2.031 2.033 2.036 2.039 2.042 3 2.045 2.048 2.051 2.053 2.056 2.059 2.062 2.065 2.068 2.071 4 2.074 2.076 2.079 2.082 2.085 2.088 2.091 2.094 2.097 2.100 1.45 2.102 2.105 2.108 2.111 2.114 2.117 2.120 2.123 2.126 2.129 6 2.132 2.135 2.137 2.140 2.143 2.146 2.149 2.152 2.155 2.158 7 2.161 2.164 2.167 2.170 2.173 2.176 2.179 2.182 2.184 2.187 8 2.190 2.193 2.196 2.199 2.202 2.205 2.208 2.211 2.214 2.217 9 2.220 2.223 2.226 2.229 2.232 2.235 2.238 2.241 2.244 2.247 Moving the decimal point ONE place in N requires moving it TWO places in body of table (see p. 6). MATHEMATICAL TABLES SQUARES (continued) N 1 2 3 4 5 6 7 8 9 ii 1.50 2.250 2.253 2.256 2.259 2.262 2.265 2.268 2.271 2.274 2.277 3 I 2.280 2.283 2.286 2.289 2.292 2.295 2.298 2.301 2.304 2.307 2 2.310 2.313 2.316 2.320 2.323 2.326 2.329 2.332 2.335 2.338 3 2.341 2.344 2.347 2.350 2.353 2.356 2.359 2.362 2.365 2.369 4 2.372 2.375 2.378 2.381 2.384 2.387 2.390 2.393 2.396 2.399 1.55 2.402 2.406 2.409 2.412 2.415 2.418 2.421 2.424 2.427 2.430 6 2.434 2.437 2.440 2.443 2.446 2.449 2.452 2.455 2.459 2.462 7 2.465 2.468 2.471 2.474 2.477 2.481 2.484 2.487 2.490 2.493 8 2.496 2.500 2.503 2.506 2.509 2.512 2.515 2.519 2.522 2.525 9 2.528 2.531 2.534 2.538 2.541 2.544 2.547 2.550 2.554 2.557 1.60 2.560 2.563 2.566 2.570 2.573 2.576 2.579 2.582 2.586 2.589 1 2.592 2.595 2.599 2.602 2.605 2.608 2.611 2.615 2.618 2.621 2 2.624 2.628 2.631 2.634 2.637 2.641 2.644 2.647 2.650 2.654 3 2.657 2.660 2.663 2.667 2.670 2.673 2.676 2.680 2.683 2.686 4 2.690 2.693 2.696 2.699 2.703 2.706 2.709 2.713 2.716 2.719 1.65 2.722 2.726 2.729 2.732 2.736 2.739 2.742 2.746 2.749 2.752 6 2.756 2.759 2762 2.766 2.769 2.772 2.776 2.779 2.782 2.786 7 2.789 2.792 2.796 2.799 2.802 2.806 2.809 2.812 2.816 2.819 8 2.822 2.826 2.829 2.832 2.836 2.839 2.843 2.846 2849 2.853 9 2.856 2.859 2.863 2.866 2.870 2.873 2.876 2.880 2.883 2.887 1.70 2.890 2.893 2.897 2.900 2.904 2.907 2.910 2.914 2.917 2.921 1 2.924 2.928 2.931 2.934 2.938 2.941 2.945 2.948 2.952 2.955 2 2.958 2.962 2.965 2.969 2.972 2.976 2.979 2.983 2.986 2.989 3 2.993 2.996 3.000 3.003 3.007 3.010 3.014 3.017 3.021 3.024 4 3.028 3.031 3.035 3.038 3.042 3.045 3.049 3.052 3.056 3.059 1.75 3.062 3.066 3.070 3.073 3.077 3.080 3.084 3.087 3.091 3.094 4 6 3.098 3.101 3.105 3.108 3.112 3.115 3.119 3.122 3.126 3.129 7 3.133 3.136 3.140 3.144 3.147 3.151 3.154 3.158 3.161 3.165 .8 3.168 3.172 3.176 3.179 3.183 3.186 3.190 3.193 3.197 3-201 9 3.204 3.208 3.211 3.215 3.218 3.222 3.226 3.229 3.233 3.236 1.80 3.240 3.244 3.247 3.251 3.254 3.258 3.262 3.265 3.269 3.272 1 3.276 3.280 3.283 3.287 3.291 3.294 3.298 3.301 3.305 3.309 2 3.312 3.316 3.320 3.323 3.327 3.331 3.334 3.338 3.342 3.345 3 3.349 3.353 3.356 3.360 3.364 3.367 3.371 3.375 3.378 3.382 4 3.386 3.389 3.393 3.397 3.400 3.404 3.408 3.411 3.415 3.419 1.85 3.422 3.426 3.430 3.434 3.437 3.441 3.445 3.448 3.452 3.456 6 3.460 3.463 3.467 3.471 3.474 3.478 3.482 3.486 3.489 3.493 7 3.497 3.501 3.504 3.508 3.512 3.516 3.519 3.523 3.527 3.531 8 3.534 3.538 3.542 3.546 3.549 3.553 3.557 3.561 3.565 3.568 9 3.572 3.576 3.580 3.583 3.587 3.591 3.595 3.599 3.602 3.606 1.90 3.610 3.614 3.618 3.621 3.625 3.629 3.633 3.637 3.640 3.644 1 3.648 3.652 3.656 3.660 3.663 3.667 3.671 3.675 3.679 3.683 2 3.686 3.690 3.694 3.698 3.702 3.706 3.709 3.713 3.717 3.721 3 3.725 3.729 3.733 3.736 3.740 3.744 3.748 3.752 3.756 3.760 4 3.764 3.767 3.771 3.775 3.779 3.783 3.787 3.791 3.795 3.799 1.95 3.802 3.806 3.810 3.814 3.818 3.822 3.826 3.830 3.834 3.838 6 3.842 3.846 3.849 3.853 3.857 3.861 3.865 3.869 3.873 3.877 7 3.881 3.885 3.889 3.893 3.897 3.901 3.905 3.909 3.912 3.916 8 3.920 3.924 3.928 3.932 3.936 3.940 3.944 3.948 3.952 3.956 9 3.960 3.964 3.968 3.972 3.976 3.980 3.984 3.988 3.992 3.996 = 9.86960 !/* = 0.101321 7.38906 MATHEMATICAL TABLES SQUARES (continued) N 1 2 3 4 5 6 7 8 9 $S 2.00 4.000 4.004 4.008 4.012 4.016 4.020 4.024 4.028 4.032 4.036 4 1 4.040 4.044 4.048 4.052 4.056 4.060 4.064 4.068 4.072 4.076 2 4.080 4.084 4.088 4.093 4.097 4.101 4.105 4.109 4.113 4.117 3 4.121 4.125 4.129 4.133 4.137 4.141 4.145 4.149 4. 153 4.158 4 4.162 4.166 4.170 4.174 4.178 4.182 4.186 4.190 4.194 4.198 2.05 4.202 4.207 4.211 4.215 4.219 4.223 4.227 4.231 4.235 4.239 6 4.244 4.248 4.252 4.256 4.260 4.264 4.268 4.272 4.277 4.281 7 4.285 4.289 4.293 4.297 4.301 4.306 4.310 4.314 4.318 4.322 8 4.326 4.331 4.335 4.339 4.343 4.347 4.351 4.356 4.360 4.364 9 4.368 4.372 4.376 4.381 4.385 4.389 4.393 4.397 4.402 4.406 2.10 4.410 4.414 4.418 4.423 4.427 4.431 4.435 4.439 4.444 4.448 1 4.452 4.456 4.461 4.465 4.469 4.473 4.477 4.482 4486 4.490 2 4.494 4.499 4.503 4.507 4.511 4.516 4.520 4.524 4.528 4533 3 4.537 4.541 4.545 4.550 4.554 4.558 4.562 4.567 4.571 4.575 4 4.580 4.584 4.588 4.592 4.597 4.601 4.605 4.610 4.614 4.618 2.15 4.622 4.627 4.631 4.635 4.640 4.644 4.648 4.653 4.657 4.661 6 4.666 4.670 4.674 4.679 4.683 4.687 4.692 4.696 4.700 4.705 7 4.709 4.713 4.718 4.722 4.726 4.731 4.735 4.739 4.744 4.748 8 4.752 4.757 4.761 4.765 4.770 4.774 4.779 4.783 4.787 4.792 9 4.796 4.800 4.805 4.809 4.814 4.818 4.822 4.827 4.831 4.836 2.20 4.840 4.844 4.849 4.853 4.858 4.862 4.866 4.871 4.875 4.880 1 4.884 4.889 4.893 4.897 4.902 4.906 4.911 4.915 4.920 4.924 2 4.928 4.933 4.937 4.942 4.946 4.951 4.955 4.960 4.964 4.968 3 4.973 4.977 4.982 4.986 4.991 4.995 5.000 5.004 5.009 5.013 4 5.018 5.022 5.027 5.031 5.036 5.040 5.045 5.049 5.054 5.058 2.25 5.062 5.067 5.072 5.076 5.081 5.085 5.090 5.094 5.099 5.103 5 6 5.108 5.112 5.117 5.121 5.126 5.130 5.135 5.139 5.144 5148 7 5.153 5.157 5.162 5.167 5.171 5.176 5.180 5.185 5.189 5.194 8 5.198 5.203 5.208 5.212 5.217 5.221 5.226 5.230 5.235 5.240 9 5.244 5.249 5.253 5.258 5.262 5.267 5.272 5.276 5.281 5.285 2.30 5.290 5.295 5.299 5.304 5.308 5.313 5.318 5.322 5.327 5.331 1 5.336 5.341 5.345 5.350 5.355 5.359 5.364 5.368 5.373 5.378 2 5.382 5.387 5.392 5.396 5.401 5.406 5.410 5.415 5.420 5.424 3 5.429 5.434 5.438 5.443 5.448 5.452 5.457 5.462 5.466 5.471 4 5.476 5.480 5.485 5.490 5.494 5.499 5.504 5.508 5.513 5.518 2.35 5.522 5.527 5.532 5.537 5.541 5.546 5.551 5.555 5.560 5.565 6 5.570 5.574 5.579 5.584 5.588 5.593 5.598 5.603 5.607 5.612 7 5.617 5.622 5.626 5.631 5.636 5.641 5.645 5.650 5.655 5.660 8 5.664 5.669 5.674 5.679 5.683 5.688 5.693 5.698 5.703 5.707 9 5.712 5.717 5.722 5.726 5.731 5.736 5.741 5.746 5.750 5.755 2.40 5.760 5.765 5.770 5.774 5.779 5.784 5.789 5.794 5.798 5.803 1 5.808 5.813 5.818 5.823 5.827 5.832 5.837 5.842 5.847 5.852 2 5.856 5.861 5.866 5.871 5.876 5.881 5.885 5.890 5.895 5.900 3 5.905 5.910 5.915 5.919 5.924 5.929 5.934 5.939 5.944 5.949 4 5.954 5.958 5.963 5.968 5.973 5.978 5.983 5.988 5.993 5.998 2.45 6.002 6.007 6.012 6.017 6.022 6.027 6.032 6.037 6.042 6.047 6 6.052 6.057 6.061 6.066 6.071 6.076 6.081 6.086 6.091 6.096 7 6.101 6.106 6.111 6.116 6.121 6.126 6.131 6.136 6.140 6.145 8 6.150 6.155 6.160 6.165 6.170 6.175 6.180 6.185 6.190 6.195 9 6.200 6.205 6.210 , 6.215 6.220 6.225 6.230 6.235 6.240 6.245 Moving the decimal point ONE place in N requires moving it TWO places in body of table (see p. G). MATHEMATICAL TABLES SQUARES (continued) N 1 2 3 4 5 6 7 8 9 2.50 6.250 6.255 6.260 6.265 6.270 6.275 6.280 6.285 6.290 6.295 5 1 6.300 6.305 6.310 6.315 6.320 6.325 6.330 6.335 6.340 6.345 2 6.350 6.355 6.360 6.366 6.371 6.376 6.381 6.386 6.391 6.396 3 6.401 6.406 6.411 6.416 6.421 6.426 6.431 6.436 6.441 6.447 4 6.452 6.457 6.462 6.467 6.472 6.477 6.482 6.487 6.492 6.497 2.55 6.502 6.508 6.513 6.518 6.523 6.528 6.533 6.538 6.543 6.548 6 6.554 6.559 6.564 6.569 6.574 6.579 6.584 6.589 6.595 6.600 7 6.605 6.610 6.615 6.620 6.625 6.631 6.636 6.641 6.646 6.651 8 6.656 6.662 6.667 6.672 6.677 6.682 6.687 6.693 6.698 6.703 9 6.708 6.713 6.718 6.724 6.729 6.734 6.739 6.744 6.750 6.755 2.60 6.760 6.765 6.770 6.776 6.781 6.786 6.791 6.7% 6.802 6.807 1 6.812 6.817 6.823 6.828 6.833 6.838 6.843 6.849 6.854 6.859 2 6.864 6.870 6.875 6.880 6.885 6.891 6.896 6.901 6906 6.912 3 6.917 6.922 6.927 6.933 6.938 6.943 6.948 6.954 6.959 6.964 4 6.970 6.975 6.980 6.985 6.991 6.996 7.001 7.007 7.012 7.017 2.65 7.022 7.028 7.033 7.038 7.044 7.049 7.054 7.060 7.065 7.070 6 7.076 7.081 7.086 7.092 7.097 7.102 7.108 7.113 7.118 7.124 7 7.129 7.134 7.140 7.145 7.150 7.156 7.161 7.166 7.172 7.177 8 7.182 7.188 7.193 7.198 7.204 7.209 7.215 7.220 7.225 7.231 9 7.236 7.241 7.247 7.252 7.258 7.263 7.268 7.274 7.279 7.285 2.70 7.290 7.295 7.301 7.306 7.312 7.317 7.322 7.328 7.333 7339 1 7.344 7.350 7.355 7.360 7.366 7.371 7.377 7.382 7.388 7.393 2 7.398 7.404 7.409 7.415 7.420 7.426 7.431 7.437 7.442 7.447 3 7.453 7.458 7.464 7.469 7.475 7.480 7.486 7.491 7.497 7.502 4 7.508 7.513 7.519 7.524 7.530 7.535 7.541 7.546 7.552 7.557 2.75 7.562 7.568 7.574 7.579 7.585 7.590 7.596 7.601 7.607 7.612 6 6 7.618 7.623 7.629 7.634 7.640 7.645 7.651 7.656 7.662 7.667 7 7.673 7.678 7.684 7.690 7.695 7.701 7.706 7.712 7.717 7.723 8 7.728 7.734 7.740 7.745 7.751 7.756 7.762 7.767 7.773 7.779 9 7.784 7.790 7.795 7.801 7.806 7.812 7.818 7.823 7.829 7.834 2.80 7.840 7.846 7.851 7.857 7.862 7.868 7.874 7.879 7.885 7.890 1 7.896 7.902 7.907 7.913 7.919 7.924 7.930 7.935 7.941 7.947 2 7.952 7.958 7.964 7.969 7.975 7.981 7.986 7.992 7.998 8003 3 8.009 8.015 8.020 8.026 8.032 8.037 8.043 8.049 8.054 8.060 4 8.066 8.071 8.077 8.083 8.088 8.094 8.100 8.105 8.111 8.117 2.85 8.122 8.128 8.134 8.140 8.145 8.151 8.157 8.162 8.168 8.174 6 8.180 8.185 8.191 8.197 8.202 8.208 8.214 8.220 8.225 8.231 7 8.237 8.243 8.248 8.254 8.260 8.266 8.271 8.277 8.283 8.289 8 8.294 8.300 8.306 8.312 8.317 8.323 8.329 8.335 8.341 8.346 9 8.352 8.358 8.364 8.369 8.375 8.381 8.387 8.393 8.398 8.404 2.90 8.410 8.416 8.422 8.427 8.433 8.439 8.445 8.451 8.456 8.462 1 8.468 8.474 8.480 8.486 8.491 8.497 8.503 8.509 8.515 8.521 2 8526 8.532 8.538 8.544 8.550 8.556 8.561 8.567 8.573 8.579 3 8.585 8.591 8.597 8.602 8.608 8.614 8.620 8.626 8.632 8.638 4 8.644 8.649 8.655 8.661 8.667 8.673 8.679 8.685 8.691 8.697 2.95 8.702 8.708 8.714 8.720 8.726 8.732 8.738 8.744 8.750 8.756 6 8.762 8.768 8.773 8.779 8.785 8.791 8.797 8.803 8.809 8.815 7 8.821 8.827 8.833 8.839 8.845 8.851 8.857 8.863 8.868 8874 8 8.880 8.886 8.892 8.898 8.904 8.910 8.916 8.922 8.928 8.934 9 8.940 8.946 8.952 8.958 8.964 8.970 8.976 8.982 8.988 8.994 I/T = 0.101321 7.38906 c MATHEMATICAL TABLES SQUARES (continued} N 1 2 3 4 5 6 7 8 9 S?a 5* 3.00 9.000 9.006 9.012 9.018 9.024 9.030 9.036 9.042 9.048 9.054 6 1 9.060 9.066 9.072 9.078 9.084 9.090 9.096 9.102 9.108 9.114 2 9.120 9.126 9.132 9.139 9.145 9.151 9.157 9.163 9.169 9.175 3 9.181 9.187 9.193 9.199 9.205 9.211 9.217 9.223 9.229 9.236 4 9.242 9.248 9.254 9.260 9.266 9.272 9.278 9.284 9.290 9.296 3.05 9.302 9.309 9.315 9.321 9.327 9.333 9.339 9.345 9.351 9.357 6 9.364 9.370 9.376 9.382 9.388 9.394 9.400 9.406 9.413 9.419 7 9.425 9.431 9.437 9.443 9.449 9.456 9.462 9.468 9.474 9.480 8 9.486 9.493 9.499 9.505 9.511 9.517 9.523 9.530 9.536 9.542 9 9.548 9.554 9.560 9.567 9.573 9.579 9.585 9.591 9.598 9.604 3.10 9.610 9.616 9.622 9.629 9.635 9.641 9.647 9.653 9.660 9.666 1 9.672 9.678 9.685 9.691 9.697 9.703 9.709 9.716 9.722 9.728 2 9.734 9.741 9.747 9.753 9.759 9.766 9.772 9.778 9.784 9.791 3 9.797 9.803 9.809 9.816 9.822 9.828 9.834 9.841 9.847 9.853 4 9.860 9.866 9.872 9.878 9.885 9.891 9.897 9.904 9.910 9.916 3.15 9.922 9.929 9.935 9.941 9.948 9.954 9.960 9.967 9.973 9.979 6 9.986 9.992 9.998 10.005 6 3.1 9.99 10.05 10.11 10.18 6 2 10.24 10.30 10.37 10.43 10.50 10.56 10.63 10.69 10.76 10.82 3 10.89 10.96 11.02 11.09 11.16 11.22 11.29 11.36 11.42 11.49 7 4 11.56 11.63 11.70 11.76 11.83 11.90 11.97 12.04 12.11 12.18 3.5 12.25 12.32 12.39 12.46 12.53 12.60 12.67 12.74 12.82 12.89 6 12.96 13.03 13.10 13.18 13.25 13.32 13.40 13.47 13.54 13.62 7 13.69 13.76 13.84 13.91 13.99 14.06 14.14 14.21 14.29 14.36 8 8 14.44 14.52 14.59 14.67 14.75 14.82 14.90 14.98 15.05 15.13 9 15.21 15.29 15.37 15.44 15.52 15.60 15.68 15.76 15.84 15.92 4.0 16.00 16.08 16.16 16.24 16.32 16.40 16.48 16.56 16.65 16.73 1 16.81 16.89 16.97 17.06 17.14 17.22 17.31 17.39 17.47 17.56 2 17.64 17.72 17.81 17.89 17.98 18.06 18.15 18.23 18.32 18.40 3 18.49 18.58 18.66 18.75 18.84 18.92 19.01 19.10 19.18 19.27 9 4 19.36 19.45 19.54 19.62 19.71 19.80 19.89 19.98 20.07 20.16 4.5 20.25 20.34 20.43 20.52 20.61 20.70 20.79 20.88 20.98 21.07 6 21.16 21.25 21.34 21.44 21.53 21.62 21.72 21.81 21.90 22.00 7 22.09 22.18 22.28 22.37 22.47 22.56 22.66 22.75 22.85 22.94 10 8 23.04 23.14 23.23 23.33 23.43 23.52 23.62 23.72 23.81 23.91 9 24.01 24.11 24.21 24.30 24.40 24.50 24.60 24.70 24.80 24.90 9.86960 (x/2) 2 = 2.46740 !/ = 0.101321 Explanation of Table of Squares (pp. 2-7). This table gives the value of N z for values of N from 1 to 10, correct to four figures. (Interpolated values may be in error by 1 in the fourth figure). To find the square of a number N outside the range from 1 to 10, note that moving the decimal point one place in column N is equivalent to moving it two places in the body of the table. For example: (3.217) 2 - 10.35; (0.03217)2 = 0.001035; (3217)* = 10350000 This table can also be used inversely, to give square roots. MATHEMATICAL TABLES SQUARES (continued) N 1 2 3 4 5 6 7 8 9 & 5.0 25.00 25.10 25.20 25.30 25.40 25.50 25.60 25.70 25.81 25.91 10 1 26.01 26.11 26.21 26.32 26.42 26.52 26.63 26.73 26.83 26.94 2 27.04 27.14 27.25 27.35 27.46 27.56 27.67 27.77 27.88 27.98 3 28.09 28.20 28.30 28.41 28.52 28.62 28.73 28.84 28.94 29.05 11 4 29.16 29.27 29.38 29.48 29.59 29.70 29.81 29.92 30.03 30.14 5.5 30.25 30.36 30.47 30.58 30.69 30.80 30.91 31.02 31.14 31.25 6 31.36 31.47 31.58 31.70 31.81 31.92 32.04 32.15 32.26 32.38 7 32.49 32.60 32.72 32.83 32.95 33.06 33.18 33.29 33.41 33.52 8 33.64 33.76 33.87 33.99 34.11 34.22 34.34 34.46 34.57 34.69 12 9 34.81 34.93 35.05 35.16 35.28 35.40 35.52 35.64 35.76 35.88 6.0 36.00 36.12 36.24 36.36 36.48 36.60 36.72 36.84 36.97 37.09 37.21 37.33 37.45 37.58 37.70 37.82 37.95 38.07 38.19 38.32 2 38.44 38.56 38.69 38.81 38.94 39.06 39.19 39.31 39.44 39.56 3 39.69 39.82 39.94 40.07 40.20 40.32 40.45 40.58 40.70 40.83 13 4 40.96 41.09 41.22 41.34 41.47 41.60 41.73 41.86 41.99 42.12 6.5 42.25 42.38 42.51 42.64 42.77 42.90 43.03 43.16 43.30 43.43 6 43.56 43.69 43.82 43.96 44.09 44.22 44.36 44.49 44.62 44.76 7 44.89 45.02 45.16 45.29 45.43 45.56 45.70 45.83 45.97 46.10 8 46.24 46.38 46.51 46.65 46.79 46.92 47.06 47.20 47.33 47.47 14 9 47.61 47.75 47.89 48.02 48.16 48.30 48.44 48.58 48.72 48.86 7.0 49.00 49.14 49.28 49.42 49.56 * 49.70 49.84 49.98 50.13 50.27 1 50.41 50.55 50.69 50.84 50.98 51.12 51.27 51.41 51.55 51.70 2 51.84 51.98 52.13 52.27 52.42 52.56 52.71 52.85 53.00 53.14 3 53.29 53.44 53.58 53.73 53.88 54.02 54.17 54.32 54.46 54.61 15 4 54.76 54.91 55.06 55.20 55.35 55.50 55.65 55.80 55.95 56.10 7.5 56.25 56.40 56.55 56.70 56.85 57.00 57.15 57.30 57.46 57.61 6 57.76 57.91 58.06 58.22 58.37 58.52 58.68 58.83 58.98 59.14 7 59.29 59.44 59.60 59.75 59.91 60.06 60.22 60.37 60.53 60.68 8 60.84 61.00 61.15 61.31 61.47 61.62 61.78 61.94 62.09 62.25 16 9 62.41 62.57 62.73 62.88 63.04 63.20 63.36 63.52 63.68 63.84 8.0 64.00 64.16 64.32 64.48 64.64 64.80 64.96 65.12 65.29 65.45 ] 65.61 65.77 65.93 66.10 66.26 66.42 66.59 66.75 66.91 67.08 2 67.24 67.40 67.57 67.73 67.90 68.06 68.23 68.39 68.56 68.72 3 68.89 69.06 69.22 69.39 69.56 69.72 69.89 70.06 70.22 70.39 17 4 70.56 70.73 70.90 71.06 71.23 71.40 71.57 71.74 71.91 72.08 8.5 72.25 72.42 72.59 72.76 72.93 73.10 73.27 73.44 73.62 73.79 6 73.96 74.13 74.30 74.48 74.65 74.82 75.00 75.17 75.34 75.52 7 75.69 75.86 76.04 76.21 76.39 76.56 76.74 76.91 77.09 77.26 8 77.44 77.62 77.79 77.97 78.15 78.32 78.50 78.68 78.85 79.03 18 9 79.21 79.39 79.57 79.74 79.92 80.10 80.28 80.46 80.64 80.82 9.0 81.00 81.18 81.36 81.54 81.72 81.90 82.08 82.26 82.45 82.63 1 82.81 82.99 83.17 83.36 83.54 83.72 83.91 84.09 84.27 84.46 2 84.64 84.82 85.01 85.19 85.38 85.56 85.75 85.93 86.12 86.30 3 86.49 86.68 86.86 87.05 87.24 87.42 87.61 87.80 87.98 88.17 19 4 88.36 88.55 88.74 88.92 89.11 89.30 89.49 89.68 89.87 90.06 9.5 90.25 90.44 90.63 90.82 91.01 91.20 91.39 91.58 91.78 91.97 6 92.16 92.35 92.54 92.74 92.93 93.12 93.32 93.51 93.70 93.90 7 94.09 94.28 94.48 94.67 94.87 95.06 95.26 95.45 95.65 95.84 8 96.04 96.24 96.43 96.63 96.83 97.02 97.22 97.42 97.61 97.81 20 9 9801 98.21 98.41 98.60 98.80 99.00 99.20 99.40 99.60 99.80 10.0 100.0 Moving the decimal point ONE place in N requires moving it TWO places in body of table (see p. 6). MATHEMATICAL TABLES CUBES OP NUMBERS N 1 2 3 4 5 6 7 8 9 II 1.00 1.000 1.003 1.006 1.009 1.012 1.015 1.018 1/21 1.024 1.027 3 1 1.030 1.033 1.036 1.040 1.043 1.046 1.049 1.052 1.055 1.058 2 1.061 1.064 1.067 1.071 1.074 1.077 1.080 1.083 1.086 1.090 3 1.093 1.096 1.099 1.102 1.106 1.109 1.112 1.115 1.118 1.122 4 1.125 1.128 1.131 1.135 1.138 1.141 1.144 1.148 1.151 1.154 1.05 1.158 .161 1.164 1.168 1.171 1.174 1.178 1.181 1.184 1.188 6 1.191 .194 1.198 1.201 1.205 1.208 1.211 1.215 1.218 1.222 7 1.225 .228 1.232 1.235 1.239 1.242 1.246 1.249 1.253 1.256 8 1.260 .263 1.267 1.270 1.274 1.277 1.281 1.284 1.288 1.291 4 9 1.295 .299 1.302 1.306 1.309 1.313 1.317 1.320 1.324 1.327 1.10 1.331 .335 1.338 1.342 1.346 1.349 1.353 1.357 1.360 1.364 1 1368 .371 1.375 1.379 1.382 1.386 1.390 1.394 1.397 1.401 2 1.405 1.409 1.412 1.416 1.420 1.424 1.428 1.431 1.435 1.439 3 1.443 1.447 1.451 1.454 1.458 1.462 1.466 1.470 1.474 1.478 4 1.482 1.485 1.489 1.493 1.497 1.501 1.505 1.509 1.513 1.517 1.15 1.521 1.525 1.529 1.533 1.537 1.541 1.545 1.549 1.553 1.557 6 1.561 1.565 1.569 1.573 1.577 1.581 1.585 1.589 1.593 1.598 7 1.602 1.606 1.610 1.614 1.618 1.622 1.626 1.631 1.635 1.639 8 1.643 1.647 1.651 1.656 1.660 1.664 1.668 1.672 1.677 1.681 9 1.685 1.689 1.694 1.698 1.702 1.706 1.711 1.715 1.719 1.724 1.20 1.728 1.732 1.737 1.741 1.745 1.750 1.754 1.758 1.763 1.767 1 1.772 1.776 1.780 1.785 1.789 1.794 1.798 1.802 1.807 1.811 2 1.816 1.820 1.825 1.829 1.834 1.838 1.843 1.847 1.852 1.856 3 1.861 1.865 1.870 1.875 1.879 1.884 1.888 1.893 1.897 1.902 4 1.907 1.911 1.916 1.920 1.925 1.930 1.934 1.939 1.944 1.948 5 1.25 1.953 1.958 1.963 1.967 1.972 1.977 1.981 1.986 1.991 1.996 6 2.000 2.005 2.010 2.015 2.019 2.024 2.029 2.034 2.039 2.044 7 2.048 2.053 2.058 2.063 2.068 2.073 2.078 2.082 2.087 2.092 8 2.097 2.102 2.107 2.112 2.117 2.122 2.127 2.132 2.137 2.142 9 2.147 2.152 2.157 2.162 2.167 2.172 2.177 2.182 2.187 2.192 1.30 2.197 2.202 Z.207 /.212 2.217 2.222 2.228 2.233 2.238 2.243 1 2.248 2.253 2.258 2.264 2.269 2.274 2.279 2.284 2.290 2.295 2 2.300 2.305 2.310 2.316 2.321 2.326 2.331 2.337 2.342 2.347 3 2.353 2.358 2.363 2.369 2.374 2.379 2.385 2.390 2.395 2.401 4 2.406 2.411 2.417 2.422 2.428 2.433 2.439 2.444 2.449 2.455 1.35 2.460 2.466 2.471 2.477 2.482 2.488 2.493 2.499 2.504 2.510 6 6 2.515 2.521 2.527 2.532 2.538 2.543 2.549 2.554 2.560 2.566 7 2,571 2.577 2.583 2.588 2.594 2.600 2.605 2.611 2.617 2.622 8 2.628 2.634 2.640 2.645 2.651 2.657 2.663 2.668 2.674 2.680 9 2.686 2.691 2.697 2.703 2.709 2.715 2.721 2.726 2.732 2.738 1.40 2.744 2.750 2.756 2.762 2.768 2.774 2.779 2.785 2.791 2.797 ] 2.803 2.809 2.815 2.821 2.827 2.833 2.839 2.845 2.851 2.857 2 2.863 2.869 2.875 2.881 2.888 2.894 2.900 2.906 2.912 2.918 3 2.924 2.930 2.936 2.943 2.949 2.955 2.961 2.967 2.974 2.980 4 2.986 2.992 2.998 3.005 3.011 3.017 3.023 3.030 3.036 3.042 1.45 3.049 3.055 3.061 3.068 3.074 3.080 3.087 3.093 3.099 3.106 6 3.112 3.119 3.125 3.131 3.138 3.144 3.151 3.157 3.164 3.170 7 3.177 3.183 3.190 3.196 3.203 3.209 3.216 3.222 3.229 3.235 8 3.242 3.248 3.255 3.262 3.268 3.275 3.281 3.288 3.295 3.301 7 9 3.308 3.315 3.321 3.328 3.335 3.341 3.348 3.355 3.362 3.368 Moving the decimal point ONE place in N requires moving it THREE places in body of table (see p. 10). MATHEMATICAL TABLES CUBES (continued) N 1 2 3 4 5 6 7 8 9 & 1.50 3.375 3.382 3.389 3.395 3.402 3.409 3.416 3.422 3.429 3.436 7 1 3.443 3.450 3.457 3.464 3.470 3.477 3.484 3.491 3.498 3.505 2 3.512 3.519 3.526 3.533 3.540 3.547 3.554 3.561 3.568 3.575 3 3.582 3.589 3.596 3.603 3.610 3.617 3.624 3.631 3.638 3.645 4 3.652 3.659 3.667 3.674 3.681 3.688 3.695 3.702 3.709 3.717 1.55 3.724 3.731 3.738 3.746 3.753 3.760 3.767 3.775 3.782 3.789 6 3.796 3.804 3.811 3.818 3.826 3.833 3.840 3.848 3.855 3.863 7 3.870 3.877 3.885 3.892 3.900 3.907 3.914 3.922 3.929 3.937 8 3.944 3.952 3.959 3.967 3.974 3.982 3.989 3.997 4.005 4.012 8 9 4.020 4.027 4.035 4.042 4.050 4.058 4.065 4.073 4.081 4.088 1.60 4.096 4.104 4.111 4.119 4.127 4.135 4.142 4.150 4.158 4.166 4.173 4.181 4.189 4.197 4.204 4.212 4.220 4.228 4.236 4.244 2 4.252 4.259 4.267 4.275 4.283 4.291 4.299 4.307 4.315 4.323 3 4.331 4.339 4.347 4355 4.363 4.371 4.379 4.387 4.395 4.403 4 4.411 4.419 4.427 4.435 4.443 4.451 4.460 4.468 4.476 4.484 1.65 4.492 4.500 4.508 4.517 4.525 4.533 4.541 4.550 4.558 4.566 6 4.574 4.583 4.591 4.599 4.607 4.616 4.624 4.632 4.641 4.649 7 4.657 4.666 4.674 4.683 4.691 4.699 4.708 4.716 4.725 4.733 8 4.742 4.750 4.759 4.767 4.776 4.784 4.793 4.801 4.810 4.818 9 4.827 4.835 4.844 4.853 4.861 4.870 4.878 4.887 4.896 4.904 9 1.70 4.913 4.922 4.930 4.939 4.948 4.956 4.965 4.974 4.983 4.991 1 5.000 5.009 5.018 5.027 5.035 5.044 5.053 5.062 5.071 5.080 2 5.088 5.097 5.106 5.115 5.124 5.133 5.142 5.151 5.160 5.169 3 5.178 5.187 5.196 5.205 5.214 5.223 5.232 5.241 5.250 5.259 4 5.268 5.277 5.286 5.295 5.304 5.314 5.323 5.332 5.341 5.350 1.75 5.359 5.369 5.378 5.387 5.396 5.405 5.415 5.424 5.433 5.442 6 5.452 5.461 5.470 5.480 5.489 5.498 5.508 5.517 5.526 5.536 7 5.545 5.555 5.564 5.573 5.583 5.592 5.602 5.611 5.621 5.630 10 8 5.640 5.649 5.659 5.668 5.678 5.687 5.697 5.707 5,716 5.726 9 5.735 5.745 5.755 5.764 5.774 5.784 5.793 5.803 5.813 5.822 1.80 5.832 5.842 5.851 5.861 5.871 .5.881 5.891 5.900 5.910 5.920 1 5.930 5.940 5.949 5.959 5.969 5.979 5.989 5.999 6.009 6.019 2 6.029 6.039 6.048 6.058 6.068 6.078 6.088 6.098 6.108 6.118 3 6.128 6.139 6.149 6.159 6. 169 6.179 6.189 6.199 6.209 6.219 4 6.230 6.240 6.250 6.260 6.270 6.280 6.291 6.301 6.311 6.321 1.85 6.332 6.342 6.352 6.362 6.373 6.383 6.393 6.404 6.414 6.424 6 6.435 6.445 6.456 6.466 6.476 6.487 6.497 6.508 6.518 6.529 7 6.539 6.550 6.560 6.571 6.581 6.592 6.602 6.613 6.623 6.634 11 8 6.645 6.655 6.666 6.677 6.687 6.698 6.708 6.719 6.730 6.741 9 6.751 6.762 6.773 6.783 6.794 6.805 6.816 6.827 6.837 6.848 1.90 6.859 6.870 6.881 6.892 6.902 6.913 6.924 6.935 6.946 6.957 1 6.968 6.979 6.990 7.001 7.012 7.023 7.034 7.045 7.056 7.067 2 7.078 7.089 7.100 7.1 11 7.122 7.133 7.144 7.156 7.167 7.178 3 7.189 7.200 7.211 7.223 7.234 7.245 7.256 7.268 7.279 7.290 4 7.301 7.313 7.324 7.335 7.347 7.358 7.369 7.381 7.392 7.403 1.95 7.415 7.426 7.438 7.449 7.461 7.472 7.484 7.495 7.507 7.518 17 6 7.530 7.541 7.553 7.564 7.576 7.587 7.599 7.610 7.622 7.634 7 7.645 7.657 7.669 7.680 7.692 7.704 7.715 7.727 7.739 7.751 8 7.762 7.774 7.786 7.798 7.810 7.821 7.833 7.845 7.857 7.869 9 7.881 7.892 7.904 7.916 7.928 7.940 7.952 7.964 7.976 7.988 = 31.0063 I/T = 0.0322515 + 10 CUBES (continued) MATHEMATICAL TABLES N C 1 2 3 4 5 6 7 8 9 *S <'-3 2.00 8.000 8.012 8.024 8.036 8.048 8.060 8.072 8.084 8.096 8.108 12 1 8.';21 8.133 8.145 8.157 8.169 8.181 8.194 8.206 8.218 8.230 2 8.242 8.255 8.267 8.279 8.291 8.304 8.316 8.328 8.341 8.353 3 8.365 8.378 8.390 8.403 8.415 8.427 8.440 8.452 8.465 8.477 4 8.490 8.502 8.515 8.527 8.540 8.552 8.565 8.577 8.590 8.603 2.05 8.615 8.628 8.640 8.653 8.666 8.678 8.691 8.704 8.716 8.729 13 6 8.742 8.755 8.767 8.780 8.793 8.806 8.818 8.831 8.844 8.857 7 8.870 8.883 8.895 8.908 8.921 8.934 8.947 8.960 8.973 8.986 8 8.999 9.012 9.025 9.038 9.051 9.064 9.077 9.090 9.103 9.116 9 9.129 9.142 9.156 9.169 9.182 9.195 9.208 9.221 9.235 9.248 2.10 9.261 9.274 9.287 9.301 9.314 9.327 9.341 9.354 9.367 9.381 1 9.394 9.407 9.421 9.434 9.447 9.461 9.474 9.488 9.501 9.515 2 9.528 9.542 9.555 9.569 9.582 9.596 9.609 9.623 9.636 9.650 14 3 9.664 9.677 9.691 9.704 9.718 9.732 9.745 9.759 9.773 9.787 4 9.800 9.814 9.828 9.842 9.855 9.869 9.883 9.897 9.911 9.925 2.15 9.938 9.952 9.966 9.980 9.994 10.008 14 2.1 9.94 10.08 10.22 10.36 10.50 14 2 10.65 10.79 10.94 11.09 11.24 11.39 11.54 11.70 11.85 12.01 15 3 12.17 12.33 12.49 12.65 12.81 12.98 13.14 13.31 13.48 13.65 16 4 13.82 14.00 14.17 14.35 14.53 14.71 14.89 15.07 15.25 15.44 18 2.5 15.62 15.81 16.00 16.19 16.39 16.58 16.78 16.97 17.17 17.37 20 6 17.58 17.78 17.98 18.19 18.40 18.61 18.82 19.03 19.25 19.47 21 7 19.68 19.90 20.12 20.35 20.57 20.80 21.02 21.25 21.48 21.72 23 8 21.95 22.19 22.43 22.67 22.91 23.15 23.39 23.64 23.89 24.14 24 9 24.39 24.64 24.90 25.15 25.41 25.67 25.93 26.20 26.46 26.73 26 3.0 27.00 27.27 27.54 27.82 28.09 28.37 28.65 28.93 29.22 29.50 28 1 29.79 30.08 30.37 30.66 30.96 31.26 31.55 31.86 32.16 32.46 30 2 32.77 33.08 33.39 33.70 34.01 34.33 34.65 34.97 35.29 35.61 32 3 35.94 36.26 36.59 36.93 37.26 37.60 37.93 38.27 38.61 38.96 34 4 39.30 39.65 40.00 40.35 40.71 41.06 41.42 41.78 42.14 42.51 36 3.5 42.88 43.24 43.61 43.99 44.36 44.74 45.12 45.50 45.88 46.27 39 6 46.66 47.05 47.44 47.83 48.23 48.63 49.03 49.43 49.84 50.24 40 7 50.65 51.06 51.48 51.90 52.31 52.73 53.16 53.58 54.01 54.44 42 8 54.87 55.31 55.74 56.18 56.62 57.07 57.51 57.96 58.41 58.86 44 9 59.32 59.78 60.24 60.70 61.16 61.63 62.10 62.57 63.04 63.52 47 4.0 64.00 64.48 64.96 65.45 65.94 66.43 66.92 67.42 67.92 68.42 49 1 68.92 69.43 69.93 70.44 70.96 71.47 71.99 72.51 73.03 73.56 52 2 74.09 74.62 75.15 75.69 76.23 76.77 77.31 77.85 78.40 78.95 54 3 79.51 80.06 80.62 81.18 81.75 82.31 82.88 83.45 84.03 84.60 58 4 85.18 85.77 86.35 86.94 87.53 88.12 88.72 89.31 89.92 90.52 59 4.5 91.12 91.73 92.35 92.96 93.58 94.20 94.82 95.44 96.07 96.70 62 6 97.34 97.97 98.61 99.25 99.90 100.54 64 6 100.5 101.2 101.8 102.5 103.2 7 7 103.8 104.5 105.2 105.8 106.5 107.2 107.9 108.5 109.2 109.9 7 8 110.6 111.3 112.0 112.7 113.4 114.1 114.8 115.5 116.2 116.9 7 9 117.6 118.4 119.1 119.8 120.6 121.3 122.0 122.8 123.5 124.3 7 Explanation of Table of Cubes (pp. 8-11). This table gives the value of N* for values of N from 1 to 10, correct to four figures. (Interpolated values may be in error by 1 in the fourth figure.) To find the cube of a number N outside the range from 1 to 10, note that moving the decimal point one place in column N is equivalent to moving it three places in the body of the table. For example: (4.852) = H4.2; (0.4852) = 0.1142; (485.2)3 = 114200000 This table may also be used inversely, to give cube roots. MATHEMATICAL TABLES 11 CUBES (continued) N 1 2 3 4 5 6 7 8 9 11 5.0 125.0 125.8 126.5 127.3 128.0 128.8 129.6 130.3 131.1 131.9 8 1 132.7 133.4 134.2 135.0 135.8 136.6 137.4 138.2 139.0 139.8 2 140.6 141.4 142.2 143.1 143.9 144.7 145.5 146.4 147.2 148.0 3 148.9 149.7 150.6 151.4 152.3 153.1 154.0 154.9 155.7 156.6 9 4 157.5 158.3 159.2 160.1 161.0 161.9 162.8 163.7 164.6 165.5 5.5 166.4 167.3 168.2 169.1 170.0 171.0 171.9 172.8 173.7 174.7 6 175.6 176.6 177.5 178.5 179.4 180.4 181.3 182.3 183.3 184.2 10 7 185.2 186.2 187.1 188.1 189.1 190.1 191.1 192.1 193.1 194.1 8 195.1 196.1 197.1 198.2 199.2 200.2 201.2 202.3 203.3 204.3 9 205.4 206.4 207.5 208.5 209.6 210.6 211.7 212.8 213.8 214.9 6.0 216.0 217.1 218.2 219.3 220.3 221.4 222.5 223.6 224.8 225.9 II 1 227.0 228.1 229.2 230.3 231.5 232.6 233.7 234.9 236.0 237.2 2 238.3 239.5 240.6 241.8 243.0 244.1 245.3 246.5 247.7 248.9 12 3 250.0 251.2 252.4 253.6 254.8 256.0 257.3 258.5 259.7 260.9 4 262.1 263.4 264.6 265.8 267.1 268.3 269.6 270.8 272.1 273.4 6.5 274.6 275.9 277.2 278.4 279.7 281.0 282.3 283.6 284.9 286.2 13 6 287.5 288.8 290.1 291.4 292.8 294.1 295.4 296.7 298.1 299.4 7 300.8 302.1 303.5 304.8 306.2 307.5 308.9 310.3 311.7 313.0 14 8 314.4 315.8 317.2 318.6 320.0 321.4 322.8 324.2 325.7 327.1 9 328.5 329.9 331.4 332.8 334.3 335.7 337.2 338.6 340.1 341.5 7.0 343.0 344.5 345.9 347.4 348.9 350.4 351.9 353.4 354.9 356.4 15 1 357.9 359.4 360.9 362.5 364.0 365.5 367.1 368.6 370.1 371.7 2 373.2 374.8 376.4 377.9 379.5 381.1 382.7 384.2 385.8 387.4 16 3 389.0 390.6 392.2 393.8 395.4 397.1 398.7 400.3 401.9 403.6 4 405.2 406.9 408.5 410.2 411.8 413.5 415.2 416.8 418.5 420.2 17 7.5 421.9 423.6 425.3 427.0 428.7 430.4 432.1 433.8 435.5 437.2 6 439.0 440.7 442.5 444.2 445.9 447.7 449.5 451.2 453.0 454.8 18 7 456.5 458.3 460.1 461.9 463.7 465.5 467.3 469.1 470.9 472.7 8 474.6 476.4 478.2 480.0 481.9 483.7 485.6 487.4 489.3 491.2 9 493.0 494.9 496.8 498.7 500.6 502.5 504.4 506.3 508.2 510.1 19 8.0 512.0 513.9 515.8 517.8 519.7 521.7 523.6 525.6 527.5 529.5 1 531.4 533.4 535.4 537.4 539.4 541.3 543.3 545.3 547.3 549.4 20 2 551.4 553.4 555.4 557.4 559.5 561.5 563.6 565.6 567.7 569.7 3 571.8 573.9 575.9 578.0 580.1 582.2 584.3 586.4 588.5 590.6 21 4 592.7 594.8 596.9 599.1 601.2 603.4 605.5 607.6 609.8 612.0 8.5 614.1 616.3 618.5 620.7 622.8 625.0 627.2 629.4 631.6 633.8 22 6 636.1 638.3 640.5 642.7 645.0 647.2 649.5 651.7 654.0 656.2 7 658.5 660.8 663.1 665.3 667.6 669.9 672.2 674.5 676.8 679.2 23 8 681.5 683.8 686.1 688.5 690.8 693.2 695.5 697.9 700.2 702.6 24 9 705.0 707.3 709.7 712.1 714.5 716.9 719.3 721.7 724.2 726.6 9.0 729.0 731.4 733.9 736.3 738.8 741.2 743.7 746.1 748.6 751.1 25 1 753.6 756.1 758.6 761.0 763.6 766.1 768.6 771.1 773.6 776.2 2 778.7 781.2 783.8 786.3 788.9 791.5 794.0 796.6 799.2 801.8 26 3 804.4 807.0 809.6 812.2 814.8 817.4 820.0 822.7 825.3 827.9 4 830.6 833.2 835.9 838.6 841.2 843.9 846.6 849.3 852.0 854.7 27 9.5 857.4 860.1 862.8 865.5 868.3 871.0 873.7 876.5 879.2 882.0 6 884.7 887.5 890.3 893.1 895.8 898.6 901.4 904.2 907.0 909.9 28 7 912.7 915.5 918.3 921.2 924.0 926.9 929.7 932.6 935.4 938.3 8 941.2 944.1 947.0 949.9 952.8 955.7 958.6 961.5 964.4 967.4 29 9 970.3 973.2 976.2 979.1 982.1 985.1 988.0 991.0 994.0 997.0 10.0 1000.0 = 3 1.0063 = 0.0322515 + Moving the decimal point ONE place in N requires moving it THREE places in body of table (see p. 10). 12 MATHEMATICAL TABLES SQUARE ROOTS OF NUMBERS N 1 2 3 4 5 6 7 8 9 <*)ttt & 1.0 1.000 1.005 1.010 1.015 1.020 1.025 1.030 1.034 1.039 1.044 5 1 1.049 1.054 1.058 1.063 1.068 1.072 1.077 1.082 1.086 1.091 2 1.095 1.100 1.105 1.109 1.114 1.118 1.122 1.127 1.131 1.136 4 3 1.140 1.145 1.149 1.153 1.158 1.162 1.166 1.170 1.175 1.179 4 1.183 1.187 1.192 1.196 1.200 1.204 1.208 1.212 1.217 1.221 1.5 1.225 1.229 1.233 1.237 1.241 1.245 1.249 1.253 1.257 1.261 6 1.265 1.269 1.273 1.277 1.281 1.285 1.288 1.292 1.296 1.300 7 1.304 1.308 1.311 1.315 1.319 1.323 1.327 1.330 1.334 1.338 8 1.342 1.345 1.349 1.353 1.356 1.360 1.364 1.367 1.371 1.375 9 1.378 1.382 1.386 1.389 1.393 1.396 1.400 1.404 1.407 1.411 2.0 1.414 1.418 1.421 1.425 1.428 1.432 1.435 1.439 1.442 1.446 1 1.449 1.453 1.456 1.459 1.463 1.466 1.470 1.473 1.476 1.480 3 2 1.483 1.487 1.490 1.493 1.497 1.500 1.503 1.507 1.510 1.513 3 1.517 1.520 1.523 1.526 1.530 1.533 1.536 1.539 1.543 1.546 4 1.549 1.552 1.556 1.559 1.562 1.565 1.568 1.572 1.575 1.578 2.5 1.581 1.584 1.587 1.591 1.594 1.597 1.600 1.603 1.606 1.609 6 1.612 1.616 1.619 1.622 1.625 1.628 1.631 1.634 1.637 1.640 7 1.643 1.646 1.649 1.652 1.655 1.658 1.661 1.664 1.667 1.670 8 1.673 1.676 1.679 1.682 1.685 1.688 1.691 1.694 1.697 1.700 9 1.703 1.706 1.709 1.712 1.715 1.718 1.720 1.723 1.726 1.729 3.0 1.732 1.735 1.738 1.741 1.744 1.746 1.749 1.752 1.755 1.758 1 1.761 1.764 1.766 1.769 1.772 1.775 1.778 1.780 1.783 1.786 2 1.789 1.792 1.794 1.797 1.800 1.803 1.806 1.808 1.811 1.814 3 1.817 1.819 1.822 1.825 1.828 1.830 1.833 1.836 1.838 1.841 4 1.844 1.847 1.849 1.852 1.855 1.857 1.860 1.863 1.865 1.868 3.5 1.871 1.873 1.876 1.879 1.881 1.884 1.887 1.889 1.892 1.895 6 1.897 1.900 1.903 1.905 1.908 1.910 1.913 1.916 1.918 1.921 7 1.924 1.926 1.929 1.931 1.934 1.936 1.939 1.942 1.944 1.947 8 1.949 1.952 1.954 1.957 1.960 1.962 1.965 1.967 1.970 1.972 9 1.975 1.977 1.980 1.982 1.985 1.987 1.990 1.992 1.995 1.997 4.0 2.000 2.002 2.005 2.007 2.010 2.012 2.015 2.017 2.020 2.022 1 2.025 2.027 2.030 2.032 2.035 2.037 2.040 2.042 2.045 2.047 2 2 2.049 2.052 2.054 2.057 2.059 2.062 2.064 2.066 2.069 2.071 3 2.074 2.076 2.078 2.081 2.083 2.086 2.088 2.090 2.093 2.095 4 2.098 2.100 2.102 2.105 2.107 2.110 2.112 2.114 2.117 2.119 4.5 2.121 2.124 2.126 2.128 2.131 2.133 2.135 2.138 2.140 2.142 6 2.145 2.147 2.149 2.152 2.154 2.156 2.159 2.161 2.163 2.166 7 2.168 2.170 2.173 2.175 2.177 2.179 2.182 2.184 2.186 2.189 8 2.191 2.193 2.195 2.198 2.200 2.202 2.205 2.207 2.209 2.211 9 2.214 2.216 2.218 2.220 2.223 2.225 2.227 2.229 2.232 2.234 yV= 1.77245 + = 0.56419 1.25331 1.64872 Explanation of Table of Square Roots (pp. 12-15). This table gives the values of \/N for values of N from 1 to 100, correct to four figures. (Interpolated values may be in error by 1 in the fourth figure.) To find the square root of a number N outside the range from 1 to 100, divide the digits of the number into blocks of two (beginning with the decimal point), and note that moving the decimal point two places in N is equivalent to moving it one place in the square root of N. For example: X/2.718 = 1.648; A/271. 8 - 16.48; V0.0002718 = 0.01648; V27.18 => 5.213; -N/2718 - 52.13; V / oTo02718 - 0.05213. MATHEMATICAL TABLES SQUARE ROOTS (continued) N 1 2 3 4 5 <* 5.0 2.236 2.238 2.241 2.243 2.245 2.247 2.249 2.252 2.254 2.256 2 1 2.258 2.261 2.263 2.265 2.267 2.269 2.272 2.274 2.276 2.278 2 2.280 2.283 2.285 2.287 2.289 2.291 2.293 2.296 2.298 2.300 3 2.302 2.304 2.307 2.309 2.311 2.313 2.315 2.317 2.319 2.322 4 2.324 2.326 2.328 2.330 2.332 2.335 2.337 2.339 2.341 2.343 6.5 2.345 2.347 2.349 2.352 2.354 2.356 2.358 2.360 2.362 2.364 6 2.366 2.369 2.371 2.373 2.375 2.377 2.379 2.381 2.383 2.385 7 2.387 2.390 2.392 2.394 2.396 2.398 2.400 2.402 2.404 2.406 8 2.408 2.410 2.412 2.415 2.417 2.419 2.421 2.423 2.425 2.427 9 2.429 2.431 2.433 2.435 2.437 2.439 2.441 2.443 2.445 2.447 6.0 2.449 2.452 2.454 2.456 2.458 2.460 2.462 2.464 2.466 2.468 1 2.470 2.472 2.474 2.476 2.478 2.480 2.482 2.484 2.486 2.488 2 2.490 2.492 2.494 2.496 2.498 2.500 2.502 2.504 2.506 2.508 3 2.510 2.512 2.514 2.516 2.518 2.520 2.522 2.524 2.526 2.528 4 2.530 2.532 2.534 2.536 2.538 2.540 2.542 2.544 2.546 2.548 6.6 2.550 2.551 2.553 2.555 2.557 2.559 2.561 2.563 2.565 2.567 6 2.569 2.571 2.573 2.575 2.577 2.579 2.581 2.583 2.585 2.587 7 2.588 2.590 2.592 2.594 2.596 2.598 2.600 2.602 2.604 2.606 8 2.608 2.610 2.612 2.613 2.615 2.617 2.619 2.621 2.623 2.625 9 2.627 2.629 2.631 2.632 2.634 2.636 2.638 2.640 2.642 2.644 7.0 2.646 2.648 2.650 2.651 2.653 2.655 2.657 2.659 2.661 2.663 1 2.665 2.666 2.668 2.670 2.672 2.674 2.676 2.678 2.680 2.681 2 2.683 2.685 2.687 2.689 2.691 2.693 2.694 2.696 2.698 2.700 3 2.702 2.704 2.706 2.707 2.709 2.711 2.713 2.715 2.717 2.718 4 2.720 2.722 2.724 2.726 2.728 2.729 2.731 2.733 2.735 2.737 7.5 2.739 2.740 2.742 2.744 2.746 2.748 2.750 2.751 2.753 2.755 6 2.757 2.759 2.760 2.762 2.764 2.766 2.768 2.769 2.771 2.773 7 2.775 2.777 2.778 2.780 2.782 2.784 2.786 2.787 2.789 2.791 8 2.793 2.795 2.796 2.798 2.800 2.802 2.804 2.805 2.807 2.809 9 2.811 2.812 2.814 2.816 2.818 2.820 2.821 2.823 2.825 2.827 8.0 2.828 2.830 2.832 2.834 2.835 2.837 2.839 2.841 2.843 2.844 2.846 2.848 2.850 2.851 2.853 2.855 2.857 2.858 2.860 2.862 2 2.864 2.865 2.867 2.869 2.871 2.872 2.874 2.876 2.877 2.879 3 2.881 2.883 2.884 2.886 2.888 2.890 2.891 2.893 2.895 2.897 4 2.898 2.900 2.902 2.903 2.905 2.907 2.909 2.910 2.912 2.914 8.5 2.915 2.917 2.919 2.921 2.922 2.924 2.926 2.927 2.929 2.931 6 2.933 2.934 2.936 2.938 2.939 2.941 2.943 2.944 2.946 2.948 7 2.950 2.951 2.953 2.955 2.956 2.958 2.960 2.961 2.963 2.965 8 2.966 2.968 2.970 2.972 2.973 2.975 2.977 2.978 2.980 2.982 9 2.983 2.985 2.987 2.988 2.990 2.992 2.993 2.995 2.997 2.998 9.0 3.000 3.002 3.003 3.005 3.007 3.008 3.010 3.012 3.013 3.015 1 3.017 3.018 3.020 3.022 3.023 3.025 3.027 3.028 3.030 3.032 2 3.033 3.035 3.036 3.038 3.040 3.041 3.043 3.045 3.046 3.048 3 3.050 3.051 3.053 3.055 3.056 3.058 3.059 3.061 3.063 3.064 4 3.066 3.068 3.069 3.071 3.072 3.074 3.076 3.077 3.079 3.081 9.5 3.082 3.084 3.085 3.087 3.089 3.090 3.092 3.094 3.095 3.097 6 3.098 3.100 3.102 3.103 3.105 3.106 3.108 3.110 3.111 3.113 7 3.114 3.116 3.118 3.119 3.121 3.122 3.124 3.126 3.127 3.129 8 3.130 3.132 3.134 3J35 3.137 3.138 3.140 3.142 3.143 3.145 9 3.146 3.148 3.150 3.151 3.153 3.154 3.156 3.158 3.159 3.161 Moving the decimal point TWO places in N requires moving it ONE place in body of table (see p. 12). 14 MATHEMATICAL TABLES SQUARE ROOTS (continued) N 1 2 3 4 5 6 7 8 9 d $* 10. 3.162 3.178 3.194 3.209 3.225 3.240 3.256 3.271 3.286 3.302 16 1. 3.317 3.332 3.347 3.362 3.376 3.391 3.406 3.421 3.435 3.450 15 2. 3.464 3.479 3.493 3.507 3.521 3.536 3.550 3.564 3.578 3.592 14 3. 3.606 3.619 3.633 3.647 3.661 3.674 3.688 3.701 3.715 3.728 4. 3.742 3.755 3.768 3.782 3.795 3.808 3.821 3.834 3.847 3.860 13 15. 3.873 3.886 3.899 3.912 3.924 3.937 3.950 3.962 3.975 3.987 6. 4.000 4.012 4.025 4.037 4.050 4.062 4.074 4.087 4.099 4.111 12 7. 4.123 4.135 4.147 4.159 4.171 4.183 4.195 4.207 4.219 4.231 8. 4.243 4.254 4.266 4.278 4.290 4.301 4.313 4.324 4.336 4.347 9. 4.359 4.370 4.382 4.393 4.405 4.416 4.427 4.438 4.450 4.461 11 20. 4.472 4.483 4.494 4.506 4.517 4.528 4.539 4.550 4.561 4.572 1. 4.583 4.593 4.604 4.615 4.626 4.637 4.648 4.658 4.669 4.680 2. 4.690 4.701 4.712 4.722 4.733 4.743 4.754 4.764 4.775 4.785 3. 4.796 4.806 4.817 4.827 4.837 4.848 4.858 4.868 4.879 4.889 10 4. 4.899 4.909 4.919 4.930 4.940 4.950 4.960 4.970 4.980 4.990 25. 5.000 5.010 5.020 5.030 5.040 5.050 5.060 5.070 5.079 5.089 6 5.099 5.109 5.119 5.128 5.138 5.148 5.158 5.167 5.177 5.187 7. 5.196 5.206 5.215 5.225 5.235 5.244 5.254 5.263 5.273 5.282 8. 5.292 5.301 5.310 5.320 5.329 5.339 5.348 5.357 5.367 5.376 9 9. 5.385 5.394 5.404 5.413 5.422 5.431 5.441 5.450 5.459 5.468 30. 5.477 5.486 5.495 5.505 5.514 5.523 5.532 5.541 5.550 5.559 5.568 5.577 5.586 5.595 5.604 5.612 5.621 5.630 5.639 5.648 2! 5.657 5.666 5.675 5.683 5.692 5.701 5.710 5.718 5.727 5.736 3. 5.745 5.753 5.762 5.771 5.779 5.788 5.797 5.805 5.814 5.822 4. 5.831 5.840 5.848 5.857 5.865 5.874 5.882 5.891 5.899 5.908 8 35. 5.916 5.925 5.933 5.941 5.950 5.958 5.967 5.975 5.983 5.992 6. 6.000 6.008 6.017 6.025 6.033 6.042 6.050 6.058 6.066 6.075 7. 6.083 6.091 6.099 6.107 6.116 6.124 6.132 6.140 6.148 6.156 8. 6.164 6.173 6.181 6.189 6.197 6.205 6.213 6.221 6.229 6.237 9. 6.245 6.253 6.261 6.269 6.277 6.285 6.293 6.301 6.309 6.317 40. 6.325 6.332 6.340 6.348 6.356 6.364 6.372 6.380 6.387 6.395 1. 6.403 6.411 6.419 6.427 6.434 6.442 6.450 6.458 6.465 6.473 2. 6.481 6.488 6.496 6.504 6.512 6.519 6.527 6.535 6.542 6.550 3. 6.557 6.565 6.573 6.580 6.588 6.595 6.603 6.611 6.618 6.626 4. 6.633 6.641 6.648 6.656 6.663 6.671 6.678 6.686 6.693 6.701 45. 6.708 6.716 6.723 6.731 6.738 6.745 6.753 6.760 6.768 6.775 7 6. 6.782 6.790 6.797 6.804 6.812 6.819 6.826 6.834 6.841 6.848 7. 6.856 6.863 6.870 6.877 6.885 6.892 6.899 6.907 6.914 6.921 8. 6.928 6.935 6.943 6.950 6.957 6.964 6.971 6.979 6.986 6.993 9. 7.000 7.007 7.014 7.021 7.029 7.036 7.043 7.050 7.057 7.064 SQUARE ROOTS OF CERTAIN FRACTIONS N VN N VN AT VN N VN N VN N VN y* 0.7071 H 0.7746 M 0.7559 H 0.3333 Hi 0.6455 M 0.7500 y& 0.5774 % 0.8944 , W 0.8452 % 0.4714 til 0.7638 iM 0.8292 g 0.8165 H 0.4082 M 0.9258 V* 0.6667 J M2 0.9574 13 /f 0.9014 0.5000 % 0.9129 M 0.3536 % 0.7454 H 0.2500 ls /fe 0.9682 94 0.8660 W 0.3780 ** 0.6124 7 ^ 0.8819 M 0.4330 to 0.1768 % 0.4472 0.6325 M H 0.5345 0.6547 H H 0.7906 0.9354 % 0.9428 0.2887 Me Me 0.5590 0.6614 B 0.1250 0.1414 MATHEMATICAL TABLES SQUARE ROOTS (continued) N 1 2 a 4 5 6 7 8 9 wsd $* 50. 7.071 7.078 7.085 7.092 7.099 7.106 7.113 7.120 7.127 7.134 7 1. 7.141 7.148 7.155 7.162 7.169 7.176 7.183 7.190 7.197 7.204 2. 7.211 7.218 7.225 7.232 7.239 7.246 7.253 7.259 7.266 7.273 3. 7.280 7.287 7.294 7.301 7.308 7.314 7.321 7.328 7.335 7.342 4. 7.348 7.355 7.362 7.369 7.376 7.382 7.389 7.396 7.403 7.409 55. 7.416 7.423 7.430 7.436 7.443 7.450 7.457 7.463 7.470 7.477 6. 7.483 7.490 7.497 7.503 7.510 7.517 7.523 7.530 7.537 7.543 7. 7.550 7.556 7.563 7.570 7.576 7.583 7.589 7.596 7.603 7.609 8. 7.616 7.622 7.629 7.635 7.642 7.649 7.655 7.662 7.668 7.675 9. 7.681 7.688 7.694 7.701 7.707 7.714 7.720 7.727 7.733 7.740 6 60. 7.746 7.752 7.759 7.765 7.772 7.778 7.785 7.791 7.797 7.804 1. 7.810 7.817 7.823 7.829 7.836 7.842 7.849 7.855 7.861 7.868 2. 7.874 7.880 7.887 7.893 7.899 7.906 7.912 7.918 7.925 7.931 3. 7.937 7.944 7.950 7.956 7.962 7.969 7.975 7.981 7.987 7.994 4. 8.000 8.006 8.012 8.019 8.025 8.031 8.037 8.044 8.050 8.056 65. 8.062 8.068 8.075 8.081 8.087 8.093 8.099 8.106 8.112 8.118 6. 8.124 8.130 8.136 8.142 8.149 8.155 8.161 8.167 8.173 8.179 7. 8.185 8.191 8.198 8.204 8.210 8.216 8.222 8.228 8.234 8.240 8. 8.246 8.252 8.258 8.264 8.270 8.276 8.283 8.289 8.295 8.301 9. 8.307 8.313 8.319 8.325 8.331 8.337 8.343 8.349 8.355 8.361 70. 8.367 8.373 8.379 8.385 8.390 8.396 8.402 8.408 8.414 8.420 1. 8.426 8.432 8.438 8.444 8.450 8.456 8.462 8.468 8.473 8.479 2. 8.485 8.491 8.497 8.503 8.509 8.515 8.521 8.526 8.532 8.538 3. 8.544 8.550 8.556 8.562 8.567 8.573 8.579 8.585 8.591 8.597 4. 8.602 8.608 8.614 8.620 8.626 8.631 8.637 8.643 8.649 8.654 75. 8.660 8.666 8.672 8.678 8.683 8.689 8.695 8.701 8.706 8.712 6. 8.718 8.724 8.729 8.735 8.741 8.746 8.752 8.758 8.764 8.769 7. 8.775 8.781 8.786 8.792 8.798 8.803 8.809 8.815 8.820 8.826 8. 8.832 8.837 8.843 8.849 8.854 8.860 8.866 8.871 8.877 8.883 9. 8.888 8.894 8.899 8.905 8.911 8.916 8.922 8.927 8.933 8.939 80. 8.944 8.950 8.955 8.961 8.967 8.972 8.978 8.983 8.989 8.994 1. 9.000 9.006 9.011 9.017 9.022 9.028 9.033 9.039 9.044 9.050 2 9.055 9.061 9.066 9.072 9.077 9.083 9.088 9.094 9.099 9.105 5 3. 9.110 9.116 9.121 9.127 9.132 9.138 9.143 9.149 9.154 9.160 4. 9.165 9.171 9.176 9.182 9.187 9.192 9.198 9.203 9.209 9.214 85. 9.220 9.225 9.230 9.236 9.241 9.247 9.252 9.257 9.263 9.268 6. 9.274 9.279 9.284 9.290 9.295 9.301 9.306 9.311 9.317 9.322 7. 9.327 9.333 9.338 9.343 9.349 9.354 9.359 9.365 9.370 9.375 8. 9.381 9.386 9.391 9.397 9.402 9.407 9.413 9.418 9.423 9.429 9. 9.434 9.439 9.445 9.450 9.455 9.460 9.466 9.471 9.476 9.482 90. 9.487 9.492 9.497 9.503 9.508 9.513 9.518 9.524 9.529 9.534 1. 9.539 9.545 9.550 9.555 9.560 9.566 9.571 9.576 9.581 9.586 2. 9.592 9.597 9.602 9.607 9.612 9.618 9.623 9.628 9.633 9.638 3. 9.644 9.649 9.654 9.659 9.664 9.670 9.675 9.680 9.685 9.690 4. 9.695 9.701 9.706 9.711 9.716 9.721 9.726 9.731 9.737 9.742 95. 9.747 9.752 9.757 9.762 9.767 9.772 9.778 9.783 9.788 9.793 6. 9.798 9.803 9.808 9.813 9.818 9.823 9.829 9.834 9.839 9.844 7. 9.849 9.854 9.859 9.864 9.869 9.874 9.879 9.884 9.889 9.894 8. 9.899 9.905 9.910 9.915 9.920 9.925 9.930 9.935 9.940 9.945 9. 9.950 9.955 9.960 9.965 9.970 9.975 9.980 9.985 9.990 9.995 = 1.77245+ 0.56419 = 1.25331 = 1.64872 Moving the decimal point TWO places in N requires moving it ONE place in body of table (seep. 12). 16 MATHEMATICAL TABLES CUBE ROOTS OF NUMBERS TV 1 2 3 4 5 6 7 8 9 * 4* 1.0 1.000 1.003 1.007 1.010 1.013 1.016 1.020 1.023 1.026 1.029 3 1 1.032 1.035 1.038 1.042 1.045 1.048 1.051 1.054 1.057 1.060 2 1.063 1.066 1.069 1.071 1.074 1.077 1.080 1.083 1.086 1.089 3 1.091 .094 1.097 .100 1.102 .105 1.108 .111 1.113 1.116 4 1.119 .121 1.124 .127 1.129 .132 1.134 .137 1.140 1.142 1.5 1.145 .147 1.150 .152 1.155 .157 1.160 .162 1.165 1.167 2 6 1.170 .172 1.174 .177 1.179 .182 1.184 .186 1.189 1.191 7 1.193 .196 1.198 .200 1.203 .205 1.207 .210 1.212 1.214 8 1.216 1.219 1.221 .223 1.225 1.228 1.230 .232 1.234 1.236 9 1.239 1.241 1.243 1.245 1.247 1.249 1.251 .254 1.256 1.258 2.0 1.260 1.262 1.264 1.266 1.268 1.270 1.272 .274 1.277 1.279 1 1.281 1.283 1.285 1.287 1.289 1.291 1.293 .295 1.297 1.299 2 1.301 .303 1.305 1.306 1.308 1.310 1.312 .314 1.316 1.318 3 1.320 1.322 1.324 1.326 1.328 1.330 1.331 .333 1.335 1.337 4 1.339 1.341 1.343 1.344 1.346 1.348 1.350 .352 1.354 1.355 2.5 1.357 1.359 1.361 1.363 1.364 1.366 1.368 .370 1.372 1.373 6 1.375 1.377 1.379 1.380 1.382 1.384 1.386 .387 1.389 1.391 7 1.392 .394 1.396 1.398 1.399 1.401 1.403 .404 1.406 1.408 I 8 1.409 1.411 1.413 1.414 1.416 .418 1.419 .421 1.423 1.424 9 1.426 .428 1.429 1.431 1.433 1.434 1.436 1.437 1.439 1.441 3.0 1.442 1.444 1.445 1.447 1.449 .450 1.452 1.453 1.455 1.457 1 1.458 1.460 1.461 1.463 1.464 .466 1.467 1.469 1.471 1.472 2 1.474 .475 1.477 1.478 1.480 1.481 1.483 1.484 1.486 1.487 3 1.489 1.490 1.492 1.493 1.495 1.496 1.498 1.499 1.501 1.502 4 1.504 1.505 1.507 1.508 1.510 1.511 1.512 1.514 1.515 1.517 3.5 1.518 1.520 1.521 1.523 1.524 1.525 1.527 1.528 1.530 1.531 6 1.533 .534 1.535 1.537 1.538 1.540 1.541 1.542 1.544 1.545 1 7 1.547 1.548 1.549 1.551 1.552 1.554 1.555 1.556 1.558 1.559 8 1.560 1.562 1.563 1.565 1.566 .567 1.569 1.570 1.571 1.573 9 1.574 1.575 1.577 1.578 1.579 1.581 1.582 1.583 1.585 1.586 4.0 1.587 1.589 1.590 1.591 1.593 1.594 1.595 1.597 1.598 1.599 1 1.601 1.602 1.603 1.604 1.606 1.607 1.608 1.610 1.611 1.612 2 1.613 1.615 1.616 1.617 1.619 1.620 1.621 1.622 1.624 1.625 3 1.626 1.627 1.629 1.630 1.631 1.632 1.634 1.635 1.636 1.637 4 1.639 1.640 1.641 1.642 1.644 1.645 1.646 1.647 1.649 1.650 4.5 1.651 1.652 1.653 1.655 1.656 1.657 1.658 1.659 1.661 1.662 6 1.663 1.664 1.666 1.667 1.668 1.669 1.670 1.671 1.673 1.674 7 1.675 1.676 1.677 1.679 1.680 1.681 1.682 1.683 1.685 1.686 8 1.687 1.688 1.689 1.690 1.692 1.693 1.694 1.695 1.696 1.697 9 1.698 1.700 1.701 1.702 1.703 1.704 1.705 1.707 1.708 1.709 1.46459 l/V^r~= 0.682784 Explanation of Table of Cube Roots (pp. 16-21). This table gives the values of \/TV for all values of TV from 1 to 1000, correct to four figures. (Interpolated values may be in error by 1 in the fourth figure.) To find the cube root of a number N outside the range from 1 to 1000, divide the digits of the number into blocks of three (beginning with the decimal point), and note that moving the decimal point three places in column N is equivalent to moving it one place in the cube root of TV. For example: y^.718 = 1.396; -y^2718 - 13.96; -^0.000002718 = 0.01396. -^27.18 = 3.007; -^27180 = 30.07; -^0.00002718 = 0.03007. ^271.8 = 6.477; -^271800 = 64.77; -^0.0002718 = 0.06477. MATHEMATICAL TABLES CUBE ROOTS (continued) 17 N 1 2 3 4 5 6 7 8 9 6.0 1.710 1.711 1712 1.713 1.715 1.716 1.717 1.718 1.719 1.720 1 1.721 1.722 1.724 1.725 1.726 1.727 1.728 1.729 1.730 1.731 2 1.732 1.734 1.735 1.736 1.737 1.738 1.739 1.740 1.741 1.742 3 1.744 1.745 1.746 1.747 1.748 1.749 1.750 1.751 1.752 1.753 4 1.754 1.755 1.757 1.758 1.759 1.760 1.761 1.762 1.763 1.764 5.5 1.765 1.766 1.767 1.768 1.769 1.771 1.772 1.773 1.774 1.775 6 1.776 1.777 1.778 1.779 1.780 1.781 1.782 1.783 1.784 1.785 7 1.786 1.787 1.788 1.789 1.790 1.792 1.793 1.794 1.795 1.796 8 1.797 1.798 1.799 1.800 1.801 1.802 1.803 1.804 1.805 1.806 9 1.807 1.808 1.809 1.810 1.811 1.812 1.813 1.814 1.815 1.816 6.0 1.817 1.818 1.819 1.820 1.821 1.822 1.823 1.824 1.825 1.826 1 1.827 1.828 1.829 1.830 1.831 1.832 1 833 1.834 1.835 1.836 2 1.837 1.838 1.839 1.840 1.841 1.842 1.843 1.844 1.845 1.846 3 1.847 1.848 1.849 1.850 1.851 1.852 1.853 1.854 1.855 1.856 4 1.857 1.858 1.859 1.860 1.860 1.861 1.862 1.863 1.864 1.865 6.5 1.866 1.867 1.868 1.869 1.870 1.871 1.872 1.873 1.874 1.875 6 1.876 1.877 1.878 1.879 1.880 1.881 1.881 1.882 1.883 1.884 7 1.885 1.886 1.887 1.888 1.889 1.890 1.891 1.892 1.893 1.894 8 1.895 1.895 1.896 1.897 1.898 1.899 1.900 1.901 1.902 1.903 9 1.904 1.905 1.906 1.907 1.907 1.908 1.909 1.910 1.911 1.912 7.0 1.913 1.914 1.915 1.916 1.917 1.917 1.918 1.919 1.920 1.921 1 1.922 1.923 1.924 1.925 1.926 1.926 1.927 1.928 1.929 1.930 2 1.931 1.932 1.933 1.934 1.935 1.935 1.936 1.937 1.938 1.939 3 1.940 1.941 1.942 1.943 1.943 1.944 1.945 1.946 1.947 1.948 4 1.949 1.950 1.950 1.951 1.952 1.953 1.954 1.955 1.956 1.957 7.5 1.957 1.958 1.959 1.960 1.961 1.962 1.963 1.964 1.964 1.965 6 1.966 1.967 1.968 1.969 1.970 1.970 1.971 1.972 1.973 1.974 7 1.975 1.976 1.976 1.977 1.978 1.979 1.980 1.981 1.981 1.982 8 1 983 1.984 1.985 1.986 1.987 1.987 1.988 1.989 1.990 1.991 9 1.992 1.992 1.993 1.994 1.995 1.996 1.997 1.997 1.998 1.999 8.0 2.000 2.001 2.002 2.002 2.003 2.004 2.005 2.006 2.007 2.007 1 2.008 2.009 2.010 2.01 1 2.012 2.012 2.013 2.014 2.015 2.016 2 2.017 2.017 2.018 2.019 2.020 2.021 2.021 2.022 2.023 2.024 3 2.025 2.026 2.026 2.027 2.028 2.029 2.030 2.030 2.031 2.032 4 2.033 2.034 2.034 2.035 2.036 2.037 2.038 2.038 2.039 2.040 8.5 2.041 2.042 2.042 2.043 2.044 2.045 2.046 2.046 2.047 2.048 6 2.049 2.050 2.050 2.051 2.052 2.053 2.054 2.054 2.055 2.056 7 2.057 2.057 2.058 2.059 2.060 2.061 2.061 2.062 2.063 2.064 8 2.065 2.065 2.066 2.067 2.068 2.068 2.069 2.070 2.071 2.072 9 2.072 2.073 2.074 2.075 2.075 2.076 2.077 2.078 2.079 2.079 9.0 2.080 2.081 2.082 2.082 2.083 2.084 2.085 2.085 2.086 2.087 1 2.088 2.089 2.089 2.090 2.091 2.092 2.092 2.093 2.094 2.095 2 2.095 2.096 2.097 2.098 2.098 2.099 2.100 2.101 2.101 2.102 3 2.103 2.104 2.104 2.105 2.106 2.107 2.107 2.108 2.109 2.110 4 2.110 2.111 2.112 2.113 2.113 . 2.114 2.115 2.116 2.116 2.117 9.5 2.118 2.119 2.119 2.120 2.121 2.122 2.122 2.123 2.124 2.125 6 2.125 2.126 2.127 2.128 2.128 2.129 2.130 2.130 2.131 2.132 7 2.133 2.133 2.134 2.135 2.136 2.136 2.137 2.138 2.139 2.139 8 2.140 2.141 2.141 2.142 2.143 2.144 2.144 2.145 2.146 2.147 9 2.147 2.148 2.149 2.149 2.150 2.151 2.152 2.152 2.153 2.154 I Moving the decimal point THREE places in N requires moving it ONE place in body of table (see p. 16). 2 18 MATHEMATICAL TABLES CUBE BOOTS (continued) N 1 2 3 4 5 6 7 8 9 ^ 1 to N = 100. Moving the decimal point TWO places in N requires moving it THREE places in body of' table. Thus: (7.23)^ = 19.44; (723.)^ = 19440; (0.0723)^ = 0.01944 (72.3)^ = 614.8; (7230.)^ = 614800; (0.723)^ = 0.6148 Used inversely, table gives M^ from M = 1 to M - 1000. Thus: (0.6148)** => 0.7230. MATHEMATICAL TABLES THREE-HALVES POWERS (continued') (See also p. 20) 23 N 1 2 3 4 5 6 7 8 9 1 2 1.015 1.419 .7530 IS 160.12 %\ .4137 JJfj 3 1.011 1.437 .7568 3*5 162.78 5?? 4 1.008 \ 1.455 J .7607 ^Q 165.39 261 .4364 jj 2 .45 6 8 9 1.006 1.003 1.002 1.001 1.000 J 1.474 ,Q 1.493 1.512 1.531 ij 1.55. 20 .7647 40 .7687 TV .7728 J .7769 11 .781. 167.95 ,,, 170.46 gi 172.91 fjf 175.32 241 177.69 g7 .4475 )no .4584 X^ .4691 2? .4796 25 .4899 JJJ .50 1.000 1.571 .7854 180.00 .5000 Interpolation may be inaccurate at these points. MATHEMATICAL TABLES .SEGMENTS OP CIRCLES, GIVEN h/D Given: h = height; D = diameter of circle. (For explanation of this table, see p. 38) Arc Area Central i angle, v Chord Arc Circumf. Q Area Ckde 2003 2003 3482 t1c .4027 ,Jg .4510 * 4 .4949 ;: .5355 Jftn 5735 .'6094 'U 9 .6435 *, .676. Jf6 .7075 JA; .7377 JJ2 .7670 ,293 .7954 276 .8230 2;x .8500 ^V .8763 ;K .9021 g* 0.9273 24R 0.9521 215 0.9764 % 1.0004 i?? 1.0239 Si 1.0472 1.070. ..0928 ...152 1.1374 1.1593 1.1810 1.2025 1.2239 1.2451 1.2661 1.2870 1.3078 1.3284 1.3694 1.3898 1.4101 1.4303 1.4505 1.4706 1.4907 1.5108 1.5308 1.5508 1.5708 22g 222 219 217 212 202 2J2 2 .0000 .0013 .0037 .0069 .0105 .0.47 .0192 .0242 .0294 .0350 .0409 .0470 .0534 .0600 .0668 .0739 .0811 .0885 .0961 .1039 .1118 .1199 .128. .1365 .1449 .1535 .1623 .1711 .1800 .1890 .1982 .2074 .2167 .2260 .2355 .2450 .2546 .2642 .2739 .2836 .2934 .3032 .3130 .3229 .3328 .3428 .3527 3727 3827 3927 ., , , IUU 0.00 770 , 22.96 A 296 32.52 956 39.90 738 46.15 ,|g 51-68 .... 56.72 504 6137 * 65.72 435 69.83 ^J] 73.74 _. 77.48 *|74 81.07 359 84.54 *347 87.89 .335 91.15 ,.., 94.31 97.40 309 .00.42 302 103.37 295 106.26 109.10 284 111.89 279 114.63 274 11734 27. 266 .20.00 122.63 263 125.23 260 127.79 256 .3033 254 132.84 .35.33 249 .37.80 247 140.25 245 .42.67 2J2 145.08 .47.48 240 .49.86 238 152.23 237 154.58 235 156.93 , 159.26 233 161.59 233 163.90 23. 166.22 232 168.52 ... .70.82 230 173.12 230 175.42 230 177.71 229 180.00 .0000 !2800 3919 .4359 !5I03 .5426 .5724 .6000 .6258 .6499 .6726 .6940 .7141 >513 .7684 .8000 .8146 .8285 .8417 .8660 .8773 .8879 .8980 .9075 .9165 .9250 .9330 .9404 .9474 .9539 .9600 .9656 .9708 .9755 .9798 .9837 .9871 .9902 .9928 .9950 .9968 .9982 .9992 .9998 1.0000 3.3 .298 241 J27 .2.4 .0000 .0638 .0903 .1108 .1282 .1436 !l705 .1826 .1940 .2048 .2.52 .2252 .2348 .244. .2532 .2620 .2706 .2789 .2871 .2952 3031 3108 .3184 3259 .3333 .3406 3478 .3550 .3620 3690 3759 3828 3896 .3963 .4030 .4097 .4.63 .4229 .4294 .4359 .4424 .4489 .4553 .4617 .4681 .4745 .4809 .4873 .4936 .5000 j{j .0000 , 7 .0017 \\ .0048 l\ .0087 ?? .0134 g .0187 , .0245 g .0308 g .0375 S{ .0446 .0520 TO .0599 JJ .0680 .0764 2; .085. J .0941 Q, .1033 2 .1127 A? .1224 II .1323 ,99 !$ 103 .1631 !< .1737 2$ .1846 JJ5 .1955 m .2066 1 .2.78 J .2292 \\i 2407 \\l .2523 ,, 7 2640 .2759 9 .2878 , .2998 ]^ .3.19 ,22 324. 22 3364 S 3487 g .3611 j|J 3735 , 3860 g 3986 \% .41.2 5? .4238 Jg .4364 . .4491 % .4618 ?i .4745 g .4873 J28 .5000 Interpolation may be inaccurate at these points. 36 MATHEMATICAL TABLES VOLUMES OF SPHERES BY HUNDREDTHS D 1 2 3 4 5 & 1.0 .5236 .5395 .5556 .5722 .5890 .6061 .6236 .6414 .65% .6781 173 .6969 .7161 .7356 .7555 .7757 .7963 .8173 .8386 .8603 .8823 208 '.2 .9048 .9276 .9508 .9743 .9983 1.0227 236 .2 1.023 1.047 1.073 1.098 1.124 25 .3 1.150 1.177 1.204 1.232 1.260 1.288 1.317 1.346 1.376 1.406 29 .4 1.437 1.468 1.499 1.531 1.563 1.596 1.630 1.663 1.697 1.732 33 1.5 1.767 1.803 1.839 1.875 1.912 1.950 1.988 2.026 2.065 2.105 38 .6 2.145 2.185 2.226 2.268 2.310 2.352 2.395 2.439 2.483 2.527 43 .7 2.572 2.618 2.664 2.711 2.758 2.806 2.855 2.903 2.953 3.003 48 8 3.054 3.105 3.157 3.209 3.262 3.315 3.369 3.424 3.479 3.535 54 .9 3.591 3.648 3.706 3.764 3.823 3.882 3.942 4.003 4.064 4.126 60 2.0 4.189 4.252 4.316 4.380 4.445 4.511 4.577 4.644 4.712 4.780 66 .1 4.849 4.919 4.989 5.0CO 5.131 5.204 5.277 5.350 5.425 5.500 73 .2 5.575 5.652 5.729 5.806 5.885 5.964 6.044 6.125 6.206 6.288 80 .3 6.371 6.454 6.538 6.623 6.709 6.795 6.882 6.970 7.059 7.148 87 .4 7.238 7.329 7.421 7.513 7.606 7.700 7.795 7.890 7.986 8.083 94 2.5 8.181 8.280 8.379 8.479 8.580 8.682 8.785 8.888 8.992 9.097 102 .6 9.203 9.309 9.417 9.525 9.634 9.744 9.855 9.966 10.079 110 .6 10.08 10.19 11 .7 10.31 10.42 10.54 10.65 10.77 10.89 11.01 11.13 11.25 11.37 12 .8 11.49 x 11.62 11.74 11.87 11.99 12.12 12.25 12.38 12.51 12.64 13 .9 12.77 12.90 13.04 13.17 13.31 13.44 13.58 13.72 13.86 14.00 14 3.0 14.14 14.28 14.42 14.57 14.71 14.86 15.00 15.15 15.30 15.45 15 .1 15.60 15.75 15.90 16.06 16.21 16.37 16.52 16.68 16.84 17.00 16 .2 17.16 17.32 17.48 17.64 17.81 17.97 18.14 18.31 18.48 18.65 17 .3 18.82 18.99 19.16 19.33 19.51 19.68 19.86 20.04 20.22 20.40 18 .4 20.58 20.76 20.94 21.13 21.31 21.50 21.69 21.88 22.07 22.26 19 3.5 22.45 22.64 22.84 23.03 23.23 23.43 23.62 23.82 24.02 24.23 20 .6 24.43 24.63 24.84 25.04 25.25 25.46 25.67 25.88 26.09 26.31 21 .7 26.52 26.74 26.95 27.17 27.39 27.61 27.83 28.06 28.28 28.50 22 .8 28.73 28.% 29.19 29.42 29.65 29.88 30.11 30.35 30.58 30.82 23 .9 31.06 31.30 31.54 31.78 32.02 32.27 32.52 32.76 33.01 33.26 25 4.0 33.51 33.76 34.02 34.27 34.53 34.78 35.04 35.30 35.56 35.82 26 .1 36.09 36.35 36.62 36.88 37.15 37.42 37.69 37.97 38.24 38.52 27 .2 38.79 39.07 39.35 39.63 39.91 40.19 40.48 40.76 41.05 41.34 28 .3 41.63 41.92 42.21 42.51 42.80 43.10 43.40 43.70 44.00 44.30 30 .4 44.60 44.91 45.21 45.52 45.83 46.14 46.45 46.77 47.08 47.40 31 4.5 47.71 48.03 48.35 48.67 49.00 49.32 49.65 49.97 50.30 50.63 33 .6 50.97 51.30 51.63 51.97 52.31 52.65 52.99 53.33 53.67 54.02 34 .7 54.36 54.71 55.06 55.41 55.76 56.12 56.47 56.83 57.19 57.54 35 .8 57.91 58.27 58.63 59.00 59.37 59.73 60.10 60.48 60.85 61.22 37 .9 61.60 61.98 62.36 62.74 63.12 63.51 63.89 64.28 64.67 65.06 38 Explanation of Table of Volumes of Spheres (pp. 36-37). Moving the decimal point one place in column D is equivalent to moving it three places in the body of the table. (D = diameter.) Volume of sphere = 7 X (diarn.) = 0.523599 X (diam.) Conversely, Diam. 1.240701 X MATHEMATICAL TABLES 37 VOLUMES OF SPHERES (continued) D 1 2 3 4 5 6 7 8 9 11 5.0 65.45 65.84 66.24 66.64 67.03 67.43 67.83 68.24 68.64 69.05 40 .1 69.46 69.87 70.28 70.69 71.10 71.52 71.94 72.36 72.78 73.20 42 .2 73.62 74.05 74.47 74.90 75.33 75.77 76.20 76.64 77.07 77.51 43 .3 77.95 78.39 78.84 79.28 79.73 80.18 80.63 81.08 81.54 81.99 45 .4 82.45 82.91 83.37 83.83 84.29 84.76 85.23 85.70 86.17 86.64 47 5.5 87.11 87.59 88.07 88.55 89.03 89.51 90.00 90.48 90.97 91.46 48 .6 91.95 92.45 92.94 93.44 93.94 94.44 94.94 95.44 95.95 96.46 50 .7 96.97 97.48 97.99 98.51 99.02 99.54 10006 52 .7 100.1 100.6 101.1 101.6 5 .8 102.2 102.7 103.2 103.8 104.3 104.8 105.4 105.9 106.4 107.0 5 .9 107.5 108.1 108.6 109.2 109.7 110.3 110.9 111.4 112.0 112.5 6 6.0 113.1 113.7 114.2 114.8 115.4 115.9 116.5 117.1 117.7 118.3 6 .1 118.8 119.4 120.0 120.6 121.2 121.8 122.4 123.0 123.6 124.2 .2 124.8 125.4 126.0 126.6 127.2 127.8 128.4 129.1 129.7 130.3 .3 130.9 131.5 132.2 132.8 133.4 134.1 134.7 135.3 136.0 136.6 .4 137.3 137.9 138.5 139.2 139.8 140.5 141.2 141.8 142.5 143.1 7 6.5 143.8 144.5 145.1 145.8 146.5 147.1 147.8 148.5 149.2 149.8 .6 150.5 151.2 151.9 152.6 153.3 154.0 154.7 155.4 156.1 156.8 .7 157.5 158.2 158.9 159.6 160.3 161.0 161.7 162.5 163.2 163.9 .8 164.6 165.4 166.1 166.8 167.6 168.3 169.0 169.8 170.5 171.3 .9 172.0 172.8 173.5 174.3 175.0 175.8 176.5 177.3 178.1 178.8 8 7.0 179.6 180.4 181.1 181.9 182.7 183.5 184.3 185.0 185.8 186.6 .1 187.4 188.2 189.0 189.8 190.6 191.4 192.2 193.0 193.8 194.6 .2 195.4 196.2 197.1 197.9 198.7 199.5 200.4 201.2 202.0 202.9 .3 203.7 204.5 205.4 206.2 207.1 207.9 208.8 209.6 210.5 211.3 .4 212.2 213.0 213.9 214.8 215.6 216.5 217.4 218.3 219.1 220.0 9 7.5 220.9 221.8 222.7 223.6 224.4 225.3 226.2 227.1 228.0 228.9 .6 229.8 230.8 231.7 232.6 - 233.5 234.4 235.3 236.3 237.2 238.1 .7 239.0 240.0 240.9 241.8 242.8 243.7 244.7 245.6 246.6 247.5 .8 248.5 249.4 250.4 251.4 252.3 253.3 254.3 255.2 256.2 257.2 10 .9 258.2 259.1 260.1 261.1 262.1 263.1 264.1 265.1 266.1 267.1 8.0 268.1 269.1 270.1 271.1 272.1 273.1 274.2 275.2 276.2 277.2 .1 278.3 279.3 280.3 281.4 282.4 283.4 284.5 285.5 286.6 287.6 .2 288.7 289.8 290.8 291.9 292.9 294.0 295.1 296.2 297.2 298.3 II 3 299.4 300.5 301.6 302.6 303.7 304.8 305.9 307.0 308.1 309.2 .4 310.3 311.4 312.6 313.7 314.8 315.9 317.0 318.2 319.3 320.4 8.5 321.6 322.7 323.8 325.0 326.1 327.3 328.4 329.6 330.7 331.9 .6 333.0 334.2 335.4 336.5 337.7 338.9 340.1 341.2 342.4 343.6 12 .7 344.8 346.0 347.2 348.4 349.6 350.8 352.0 353.2 354.4 355.6 .8 356.8 358.0 359.3 360.5 361.7 362.9 364.2 365.4 366.6 367.9 .9 1 369.1 370.4 371.6 372.9 374.1 375.4 376.6 377.9 379.2 380.4 13 9.0 381.7 383.0 384.3 385.5 386.8 388.1 389.4 390.7 392.0 393.3 .1 394.6 395.9 397.2 398.5 399.8 401.1 402.4 403.7 405.1 406.4 2 407.7 409.1 410.4 411.7 413.1 414.4 415.7 417.1 418.4 419.8 .3 421.2 422.5 423.9 425.2 426.6 428.0 429.4 430.7 432.1 433.5 14 .4 434.9 436.3 437.7 439.1 440.5 441.9 443.3 444.7 446.1 447.5 9.5 448.9 450.3 451.8 453.2 454.6 456.0 457.5 458.9 460.4 461.8 .6 463.2 464.7 466.1 467.6 469.1 470.5 472.0 473.5 474.9 476.4 15 .7 477.9 479.4 480.8 482.3 483.8 485.3 486.8 488.3 489.8 491.3 .8 492.8 494.3 495.8 497.3 498.9 500.4 501.9 503.4 505.0 506.5 16 9 508.0 509.6 511.1 512.7 514.2 515.8 517.3 518.9 520.5 522.0 10.0 523.6 Moving the decimal point ONE place in D requires moving it THREE places in body of table (see p. 36). 38 MATHEMATICAL TABLES SEGMENTS OF SPHERES (h = height of segment; D = diam. of sphere) h Vol. segm. to Q Vol. segm. d S Explanation of Table on this page Given, h = height of segment, D = diam. of sphere. D D Vol. sphere 0.00 1 0.0000 0002 2 0.0000 0003 3 2 0.0006 4 0.0012 9 To find the volume of the segment, 3 0.0014 10 0.0026 21 form the ratio h/D and find from the 4 0.0024 14 0.0047 / 1 26, table the value of (vol./D 8 ); then, by 0.05 0.0038 1 f 0.0073 of a simple multiplication, 6 g 0.0054 0.0073 0095 lo 19 22 0.0104 0.0140 0182 31 36 42 vol. segment = D* X (vo\./D*) The table gives also the ratio of the 9 0.0120 25 *>7 0.0228 46 11 volume of the segment to the entire 0.10 1 0.0147 0176 LI 29 0.0280 0336 _>/ 56 volume of the sphere. NOTE. Area of zone = v X h X D. 2 0.0208 32 A 0.0397 61 // (Use Table of Multiples of ir, p. 28) 3 0242 34 0463 oo 4 0.0279 37 39 0.0533 70 74 Explanation of Table on p. 34 0.15 6 0.0318 0359 41 0.0607 0686 79 Given, h = height of segment, c = chord. 7 0.0403 44 AC 0.0769 83 QA To find the diam. of the circle, the 8 9 0.0448 0.0495 4-> 47 50 0.0855 0.0946 OO 91 94 length of arc, or the area of the seg- ment, form the ratio h/c, and find 0.20 0.0545 C 1 0.1040 QO from the table the value of (diam./c), 1 2 3 0.05% 0.0649 0704 >] 53 55 0.1138 0.1239 1344 Vo 101 105 (arc/c), or (area/Ac) ; then, by a simple multiplication, 4 0.0760 56 58 0.1452 108 110 diam. = c X (diam./c), arc = c X (arc/c), 0.25 6 0.0818 0878 60 0.1562 1676 114 area = h X c X (area/Ac). 7 0.0939 61 0.1793 117 i on The table gives also the angle sub- 8 0.1002 63 64 0.1913 120 122 tended at the center, and the ratio of 9 0.1066 65 0.2035 125 h to D. See p. 106. 0.30 1 0.1131 1198 67 0.2160 2287 127 Explanation of Table on p. 35 2 0.1265 67 Xrt 0.2417 130 Given, h = height of segment, 3 0.1334 ov 70 0.2548 134 D diam. of circle. 4 0.1404 /u 71 0.2682 135 To find the chord, the length of arc, 0.35 0.1475 ni 0.2817 1 Ifl or the area of the segment, form the 6 7 8 0.1547 0.1620 0.1694 n 73 74 0.2955 0.3094 0.3235 1 JO 139 141 ratio h/D, and find from the table the value of (chord/D), (arc/Z>), or 9 0.1768 74 75 0.3377 142 143 (area//) 2 ); then, by a simple multi- MJ plication, 0.40 0.1843 0.1919 76 0.3520 0.3665 145 chord = D X (chord/ D), 2 0.1995 76 77 0.3810 145 147 arc - D X (arc//)), 3 4 0.2072 0.2149 II 77 78 0.3957 0.4104 It/ 147 148 area = D* X (area/Z)"). The table gives also the angle sub- 0.45 0.2227 70 0.4252 1 AQ tended at the center, the ratio of the 6 7 8 0.2305 0.2383 2461 7o 78 78 0.4401 0.4551 4700 1^7 150 149 arc of the segment to the whole cir- cumference, and the ratio of the area 9 0.2539 78 79 . 0.4850 150 150 of the segment to the area of the whole circle. See p. 106. 0.50 0.2618 0.5000 NOTE. Vol. segm. - }6 * h* (3D-2h). MATHEMATICAL TABLES 39 REGULAR POLYGONS n = number of sides; TO = 360/n = angle subtended at the center by one side; a = length of one side = R (2 sin |-) = r (2 tan |-) ; R = radius of circumscribed circle = a ( y^ esc \ = r (sec -^-j ; r = radius of inscribed circle = R(COS J = a(l$ cot s~J ; Area = o*H n cot - = fl'/i n sin t> = r*n tan -. Area Area Area * R a a r r n 7) a2 # r2 r R r R a 3 120 0.4330 1.299 5:196 0.5774 2.000 1.732 3.464 0.5000 0.2887 4 90 1.000 2.000 4.000 0.7071 .414 1.414 2.000 0.7071 0.5000 5 72 1.721 2.378 3.633 0.8507 .236 1.176 1.453 0.8090 0.6882 6 . 60 2.598 2.598 3.464 1.0000 .155 1.000 1.155 0.8660 0.8660 7 5P.43 3.634 2.736 3.371 1.152 .110 0.8678 0.9631 0.9010 1.038 8 45 4.828 2.828 3.314 1.307 .082 0.7654 0.8284 0.9239 1.207 9 40 6.182 2.893 3.276 1.462 .064 0.6840 0.7279 0.9397 1.374 10 36 7.694 2.939 3.249 1.618 .052 0.6180 0.6498 0.9511 1.539 12 30 11.20 3.000 3.215 1.932 .035 0.5176 0.5359 0.9659 1.866 15 24 17.64 3.051 3.188 2.405 .022 0.4158 0.4251 0.9781 2.352 16 22. 50 20.11 3.062 3.183 2.563 .020 0.3902 0.3978 0.9808 2.514 20 18 31.57 3.090 3.168 3.1% .013 0.3129 0.3168 0.9877 3.157 24 15 45.58 3.106 3.160 3.831 .009 0.2611 0.2633 0.9914 3.798 32 11.25 81.23 3.121 3.152 5.101 .005 0.1960 0.1970 0.9952 5.077 48 7. 50 183.1 3.133 3.146 7.645 .002 0.1308 0.1311 0.9979 7.629 64 5.625 325.7 3.137 3.144 10.19 .001 0.0981 0.0983 0.9988 10.18 BINOMIAL COEFFICIENTS (For table giving binomial coefficients for fractional values of n, see p. 116). n(n - 1) n(n - l)(n - 2) (n)o = 1; (n)i = n; (71)2 = (n) 1X2' n(n - l)(n - 2) . . . (n - [r - 1]). 1X2X3. . . X r 1X2X3 Another notation: = (n) r . n (n)o ()i (n)i (n)i (n)* (n). (n)a ()T (n)a (n)a (n)w (n)u (n)is (n)i3 I 1 ? 2 1 3 3 3 1 4 4 6 4 1 5 5 10 10 5 1 6 6 15 20 15 6 1 7 7 21 35 35 71 7 1 8 8 28 56 70 56 28 8 1 Q 9 36 84 126 126 84 36 9 1 in 10 45 120 210 252 210 120 45 10 | 11 11 51 165 310 462 462 330 165 55 11 1 12 13 14 15 12 13 14 15 66 78 91 105 220 286 364 455 495 715 1001 1365 792 1287 2002 3003 924 1716 3003 5005 792 1716 3432 6435 495 1287 3003 6435 220 715 2002 5005 66 286 1001 3003 12 78 364 1365 1 13 91 455 ..... 14 105 For n = 14, (n)u = 1; for n - 15, (n)u = 15, and (n) l6 - 1. 40 MATHEMATICAL TABLES COMMON LOGARITHMS (special table) 1* 1 2 3 4 5 6 7 8 9 $? JTJ 1.00 0.0000 0004 0009 0013 0017 0022 0026 0030 0035 0039 4 1.01 0043 0048 0052 0056 0060 0065 0069 0073 0077 0082 1.02 0086 0090 0095 0099 0103 0107 0111 0116 0120 0124 1.03 0128 0133 0137 0141 0145 0149 0154 0158 0162 0166 1.04 0170 0175 0179 0183 0187 0191 0195 0199 0204 0208 1.05 0212 0216 0220 0224 0228 0233 0237 0241 0245 0249 1.06 0253 0257 0261 0265 0269 0273 0278 0282 0286 0290 1.07 0294 0298 0302 0306 0310 0314 0318 0322 0326 0330 .08 0334 0338 0342 0346 0350 0354 0358 0362 0366 0370 1.09 0374 0378 0382 0386 0390 0394 0398 0402 04C6 0410 .10 0.0414 0418 0422 0426 0430 0434 0438 0441 0445 0449 .11 0453 0457 0461 0465 0469 0473 . 0477 0481 0484 0488 .12 0492 0496 0500 0504 0508 0512 0515 0519 0523 0527 .13 0531 0535 0538 0542 0546 0550 0554 0558 0561 0565 .14 0569 0573 0577 0580 0584 0588 0592 0596 0599 0603 .15 0607 0611 0615 0618 0622 0626 0630 0633 0637 0641 .16 0645 0648 0652 0656 0660 0663 0667 0671 0674 0678 .17 0682 0686 0689 0693 0697 0700 0704 0708 0711 0715 .18 0719 0722 0726 0730 0734 0737 0741 0745 0748 0752 .19 0755 0759 0763 0766 0770 0774 0777 0781 0785 0788 x . 1.20 0.0792 0795 0799 0303 0806 0810 0813 0817 0821 0824 1.21 0828 0831 0835 0839 0842 0846 0849 0853 0856 0860 1.22 0864 0867 0871 0374 0878 0881 0885 0888 0892 0896 1.23 0899 0903 0906 0910 0913 0917 0920 0924 0927 0931 1.24 0934 0938 0941 0945 0948 0952 0955 0959 0962 0966 1.25 0969 0973 0976 0980 0983 0986 0990 0993 0997 1000 3 1.26 1004 1007 1011 1014 1017 1021 1024 1028 1031 1035 1.27 1038 1041 1045 1048 1052 1055 1059 1062 1065 1069 1.28 1072 1075 1079 1082 1086 1089 1092 1096 1099 1103 1.29 1106 1109 1113 1116 1119 1.123 1126 1129 1133 1136 1.30 0.1139 1143 1146 1149 1153 1156 1159 1163 1166 1169 1.31 1173 1176 1179 1183 1186 1189 1193 1196 1199 1202 1.32 1206 1209 1212 1216 1219 1222 1225 1229 1232 1235 1.33 1239 1242 1245 1248 1252 1255 1258 1261 1265 1268 1.34 1271 1274 1278 1281 1284 1287 1290 1294 1297 1300 1.35 1303 1307 1310 1313 1316 1319 1323 1326 1329 1332 1.36 1335 1339 1342 1345 1348 1351 1355 1358 1361 1364 1.37 1367 1370 1374 1377 1380 1383 1386 1389 1392 1396 1.38 1399 1402 1405 1408 1411 1414 1418 1421 1424 1427 1.39 1430 1433 1436 1440 1443 1446 1449 1452 1455 1458 1.40 0.1461 1464 1467 1471 1474 1477 1480 1483 1486 1489 1.41 1492 1495 1498 1501 1504 1508 1511 1514 1517 1520 1.42 1523 1526 1529 1532 1535 1538 1541 1544 1547 1550 1.43 1553 1556 1559 1562 1565 1569 1572 1575 1578 1581 1.44 1584 1587 1590 1593 1596 1599 1602 1605 1608 1611 1.45 1614 1617 1620 1623 1626 1629 1632 1635 1638 1641 1.46 1644 1647 1649 1652 1655 1658 1661 1664 1667 1670 1.47 1673 1676 1679 1682 1685 1688 1691 1694 1697 1700 1.48 1703 1706 1708 1711 1714 1717 1720 1723 1726 1729 1.49 1732 1735 1738 1741 1744 1746 1749 1752 1755 1758 Moving the decimal point n places to the right [or left] in the number requires adding + n [or - n] ia the body of the table (see p. 42). MATHEMATICAL TABLES 41 COMMON LOGARITHMS (special table, continued) p 1 2 3 4 5 6 7 8 9 11 1.50 0.1761 1764 1767 1770 1772 1775 . 1778 1781 1784 1787 3 1.51 1790 1793 1796 1798 1801 1804 1807 1810 1813 1816 1.52 1818 1821 1824 1827 1830 1833 1836 1838 1841 1844 1.53 1847 1850 1853 1855 1858 1861 1864 1867 1870 1872 1.54 1875 1878 1881 1884 1886 1889 1892 1895 1898 1901 1.55 1903 1906 1909 1912 19t5 1917 1920 1923 1926 1928 1.56 1931 1934 1937 1940 1942 1945 1948 1951 1953 1956 1.57 1959 1962 1965 1967 1970 1973 1976 1978 1981 1984 1.58 1987 1989 1992 1995 1998 2000 2003 2006 2009 2011 1.59 2014 2017 2019 2022 2025 2028 2030 2033 2036 2038 1.60 0.2041 2044 2047 2049 2052 2055 2057 2060 2063 2066 1.61 2068 2071 2074 2076 2079 2082 2084 2087 2090 2092 1.62 2095 2098 2101 2103 2106 2109 2111 2114 2117 2119 1.63 2122 2125 2127 2130 2133 2135 2138 2140 2143 2146 1.64 2148 2151 2154 2156 2159 2162 2164 2167 2170 2172 1.65 2175 2177 2180 2183 2185 2188 2191 2193 2196 2198 1.66 2201 2204 2206 2209 2212 2214 2217 2219 2222 2225 1.67 2227 2230 2232 2235 2238 2240 2243 2245 2248 2251 1.68 2253 2256 2258 2261 2263 2266 2269 2271 2274 2276 1.69 2279 2281 2284 2287 2289 2292 2294 2297 2299 2302 1.70 0.2304 2307 2310 2312 2315 2317 2320 2322 2325 2327 1.71 2330 2333 2335 2338 2340 2343 2345 2348 2350 2353 1.72 2355 2358 2360 2363 2365 2368 2370 2373 2375 2378 1.73 2380 2383 2385 2388 2390 2393 2395 2398 2400 2403 1.74 2405 2408 2410 2413 2415 2418 2420 2423 2425 2428 2 1.75 2430 2433 2435 2438 2440 2443 2445 2448 2450 2453 1.76 2455 2458 2460 2463 2465 2467 2470 2472 2475 2477 1.77 2480 2482 2485 2487 2490 2492 2494 2497 2499 2502 1.78- 2504 2507 2509 2512 2514 2516 2519 2521 2524 2526 1.79 2529 2531 2533 2536 2538 2541 2543 2545 2548 2550 180 0.2553 2555 2558 2560 2562 2565 2567 2570 2572 2574 1.81 2577 2579 2582 2584 2586 2589 2591 2594 2596 2598 1.82 2601 2603 2605 2608 2610 2613 2615 2617 2620 2622 1.83 2625 2627 2629 2632 2634 2636 2639 2641 2643 2646 1.84 2648 2651 2653 2655 2658 2660 2662 2665 2667 2669 1.85 2672 2674 2676 2679 2681 2683 2686 2688 2690 2693 1.86 2695 2697 2700 2702 2704 2707 2709 2711 2714 2716 1.87 2718 2721 2723 2725 2728 2730 2732 2735 2737 2739 1.88 2742 2744 2746 2749 2751 2753 2755 2758 2760 2762 1.89 2765 2767 2769 2772 2774 2776 2778 2781 2783 2785 1.90 0.2788 2790 2792 2794 2797 2799 2801 2804 2806 2808 1.91 2810 2813 2815 2817 2819 2822 2824 ' 2826 2828 2831 1.92 2833 2835 2838 2840 2842 2844 2847 2849 2851 2853 1.93 2856 2858 2860 2862 2865 2867 2869 2871 2874 2876 1.94 2878 2880 2882 2885 2887 2889 2891 2894 2896 2898 1.95 2900 2903 2905 2907 2909 2911 2914 2916 2918 2920 1.96 2923 2925 2927 2929 2931 2934 2936 2938 2940 2942 1.97 2945 2947 2949 2951 2953 2956 2958 2960 2962 2964 1.98 2967 2969 2971 2973 2975 2978 2980 2982 2984 2986 1.99 2989 2991 2993 2995 2997 2999 3002 3004 3006 3008 42 MATHEMATICAL TABLES COMMON LOGARITHMS 11 1 2 a 4 5 6 7 8 9 Sa <3-0 1.0 0.0000 0043 0086 0128 0170 0212 0253 0294 0334 0374 1.1 0414 0453 0492 0531 0569 0607 0645 0682 0719 0755 1.2 0792 0828 0864 0899 0934 0969 1004 1038 1072 1106 TH 1.3 1139 1173 1206 1239 1271 1303 1335 1367 1399 1430 1 1.4 1461 1492 1523 1553 1584 1614 1644 1673 1703 1732 6 ^ 13 1761 1790 1818 1847 1875 1903 1931 1959 1987 2014 1 1.6 2041 2068 2095 2122 2148 2175 2201 2227 2253 2279 03 1.7 2304 2330 2355 2380 2405 2430 2455 2480 2504 2529 ft 1.8 2553 2577 2601 2625 2648 2672 2695 2718 2742 2765 1 1.9 2788 2810 2833 2856 2878 2900 2923 2945 2967 2989 CQ 2.0 0.3010 3032 3054 3075 3096 3118 3139 3160 3181 3201 21 2.1 3222 3243 3263 3284 3304 3324 3345 3365 3385 3404 20 2.2 3424 3444 3464 3483 3502 3522 3541 3560 3579 3598 19 2.3 3617 3636 3655 3674 3692 3711 3729 3747 3766 3784 18 2.4 3802 3820 3838 3856 3874 3892 3909 3927 3945 3962 17 2.5 3979 3997 4014 4031 4048 4065 4082 4099 4116 4133 17 2.6 4150 4166 4183 4200 4216 4232 4249 4265 4281 4298 16 2.7 4314 4330 4346 4362 4378 4393 4409 4425 4440 4456 16 2.8 4472 4487 4502 4518 4533 4548 4564 4579 4594 4609 15 2.9 4624 4639 4654 4669 4683 4698 4713 4728 4742 4757 15 3.0 0.4771 4786 4800 4814 4829 4843 4857 4871 4886 4900 14 3.1 4914 4928 4942 4955 4969 4983 4997 5011 5024 5038 14 3.2 5051 5065 5079 5092 5105 5119 5132 5145 5159 5172 13 3.3 5185 5198 5211 5224 5237 5250 5263 5276 5289 5302 13 3.4 5315 5328 5340 5353 5366 5378 5391 5403 5416 5428 13 3.5 5441 5453- 5465 5478 5490 5502 5514 5527 5539 5551 12 3.6 5563 5575 5587 5599 5611 5623 5635 5647 5658 5670 12 3.7 5682 5694 5705 5717 5729 5740 5752 5763 5775 5786 12 3.8 5798 5809 5821 5832 5843 5855 5866 5877 5888 5899 11 3.9 5911 5922 5933 5944 5955 5966 5977 5988 5999 6010 11 4.0 0.6021 6031 6042 6053 6064 6075 6085 6096 6107 6117 11 4.1 6128 6138 6149 6160 6170 6180 6191 6201 6212 6222 10 4.2 6232 6243 6253 6263 6274 6284 6294 6304 6314 6325 10 4.3 6335 6345 6355 6365 6375 6385 6395 6405 6415 6425 10 4.4 6435 6444 6454 6464 6474 6484 6493 6503 6513 6522 10 4.5 6532 6542 6551 6561 6571 6580 6590 6599 6609 6618 10 4.6 6628 6637 6646 6656 6665 6675 6684 6693 6702 6712 10 4.7 6721 6730 6739 6749 6758 6767 6776 6785 6794 6803 9 4.8 6812 6821 6830 6839 6848 6857 6866 6875 6884 6893 9 4.9 6902 6911 6920 6928 6937 6946 6955 6964 6972 6981 9 log TT = 0.4971 log e = 0.4343 log 7T/2 = 0.1961 log 71-2 log (0.4343) = 0.6378 - 1 0.9943 log 0.2486 These two pages give the common logarithms of numbers between 1 and 10, correct to four places. Moving the decimal point n places to the right [or left] in the number is equivalent to adding n[dr-n] to the logarithm. Thus, log 0.017453 = 0.2419 - 2, which may also be written 2.2419 or 8.2419 - 10. See p. 91. Graphs, p. 174. log (aft) = log a + log 6 log (a N ) = N log a log = log a - log 6 log - log a MATHEMATICAL TABLES 43 COMMON LOGARITHMS (continued) 1* 1 2 3 4 5 6 7 8 9 !i 5.0 0.6990 6998 7007 7016 7024 7033 7042 7050 7059 7067 9 5.1 7076 7084 7093 7101 7110 7118 7126 7135 7143 7152 8 5.2 7160 7168 7177 7185 7193 7202 7210 7218 7226 7235 8 5.3 7243 7251 7259 7267 7275 7284 7292 7300 7308 7316 8 5.4 7324 , 7332 7340 7348 7356 7364 7372 7380 7388 7396 8 5.5 7404 7412 7419 7427 7435 7443 7451 7459 7466 7474 8 5.6 7482 7490 7497 7505 7513 7520 7528 7536 7543 7551 8 5.7 7559 > 7566 7574 7582 7589 7597 7604 7612 7619 7627 8 5.8 7634 7642 7649 7657 7664 7672 7679 7686 7694 7701 7 5.9 7709 7716 7723 7731 7738 7745 7752 7760 7767 7774 7 6.0 0.7782 7789 7796 7803 7810 7818 7825 7832 7839 7846 7 6.1 7853 7860 7868 7875 7882 7889 7896 7903 7910 7917 7 6.2 7924 7931 7938 7945 7952 7959 7966 7973 7980 7987 7 6.3 7993 8000 8007 8014 8021 8028 8035 8041 8048 8055 7 6.4 8062 8069 8075 8082 8089 8096 . 8102 8109 8116 8122 7 6.5 8129 8136 8142 8149 8156 8162 8169 8176 8182 8189 7 6.6 8195 8202 8209 8215 8222 8228 8235 8241 8248 8254 7 6.7 8261 8267 8274 8280 8287 8293 8299 8306 8312 8319 6 6.8 8325 8331 8338 8344 8351 8357 8363 8370 8376 8382 6 6.9 8388 8395 8401 8407 8414 8420 8426 8432 8439 8445 6 7.0 0.8451 8457 8463 8470 8476 8482 8488 8494 8500 8506 6 7.1 1 8513 8519 8525 8531 8537 8543 8549 8555 8561 8567 6 7.2 8573 8579 8585 8591 8597 8603 8609 8615 8621 8627 6 7.3 8633 8639 8645 8651 8657 8663 8669 8675 8681 8686 6 7.4 8692 8698 8704 8710 8716 8722 8727 8733 8739 8745 6 7.5 8751 8756 8762 8768 8774 8779 8785 8791 8797 8802 6 7.6 8808 8814 8820 8825 8831 8837 8842 8848 8854 8859 6 7.7 8865 8871 8876 8882 8887 8893 8899 8904 8910 8915 6 7.8 8921 8927 8932 8938 8943 8949 8954 8960 8965 8971 6 7.9 8976 8982 8987 8993 8998 9004 9009 9015 9020 9025 5 8.0 0.9031 9036 9042 9047 9053 9058 9063 9069 9074 9079 5 8.1 9085 9090 9096 9101 9106 9112 9117 9122 9128 9133 5 8.2 9138 9143 9149 9154 9159 9165 9170 9175 9180 9186 5 8.3 9191 9196 9201 9206 9212 9217 9222 9227 9232 9238 5 8.4 9243 9248 9253 9258 9263 . 9269 9274 9279 9284 9289 5 8.5 9294 9299 9304 9309 9315 9320 9325 9330 9335 9340 5 8.6 9345 9350 9355 9360 9365 9370 9375 9380 9385 9390 5 8.7 9395 9400 9405 9410 9415 9420 9425 9430 9435 9440 5 8.8 9445 9450 9455 9460 9465 9469 9474 9479 9484 9489 5 8.9 9494 . 9499 9504 9509 9513 9518 9523 9528 9533 9538 5 9.0 0.9542 9547 9552 9557 9562 9566 9571 9576 9581 9586 5 9.1 9590 9595 9600 9605 9609 9614 9619 9624 9628 9633 5 9.2 9638 9643 9647 9652 9657 9661 9666 9671 9675 9680 5 9.3 9685 9689 9694 9699 9703 9708 9713 9717 9722 9727 5 9.4 9731 9736 9741 9745 9750 , 9754 9759 9763 9768 9773 5 9.5 9777 9782 9786 9791 9795 9800 9805 9809 9814 9818 5 9.6 9823 9827 9832 9836 9841 9845 9850 9854 9859 9863 4 9.7 9868 9872 9877 9881 9886 9890 9894 9899 9903 9908 4 9.8 99 r2- - 9917 9921 9926 9930 9934 9939 9943 9948 9952 4 9.9 9956 9961 9965 9969 9974 9978 9983 9987 9991 9996 4 44 MATHEMATICAL TABLES DEGREES AND MINUTES EXPRESSED IN RADIANS (See also p. 69) Degrees Hundredths Minutes 1 .0175 61 1.0647 121 2.1118 0.01 .0002 0.51 .0089 r .0003 2 .0349 2 1.0821 2 2.1293 2 .0003 2 .0091 2' .0006 3 .0524 3 .0996 3 2.1468 3 .0005 3 .0093 3' .0009 4 .0698 4 .1170 4 2.1642 4 .0007 4 .0094 4' .0012 5 .0873 65 .1345 125 2.1817 .05 .0009 .55 .0096 5' .0015 6 .1047 6 .1519 6 2.1991 6 .0010 6 .0098 6' .0017 7 .1222 7 .1694 7 2.2166 7 .0012 7 .0099 7' .0020 8 .1396 8 .1868 8 2.2340 8 .0014 8 .0101 8' .0023 9 .1571 9 1.2043 9 2.2515 9 .0016 9 .0103 9' .0026 10 .1745 70 1.2217 130 2.2689 0.10 .0017 0.60 .0105 10' .0029 .1920 1 1.2392 1 2.2864 1 .0019 ] .0106 11' .0032 2 .2094 2 1.2566 2 2.3038 2 .0021 2 .0108 12' .0035 3 .2269 3 1.2741 3 2.3213 3 .0023 3 .0110 13' .0038 4 .2443 4 1.2915 4 2.3387 4 .0024 4 .0112 14' .0041 15 .2618 75 1.3090 136 2.3562 .15 .0026 .65 .0113 15' 0044 6 .2793 6 1.3265 6 2.3736 6 .0028 6 .0115 16' .0047 7 .2967 7 1.3439 7 2.3911 7 .0030 7 .0117 17' .0049 8 .3142 8 1,3614 8 2.4086 8 .0031 8 .0119 18' .0052 9 .3316 9 1.3788 9 2.4260 9 .0033 9 .0120 19' .0055 20 .3491 80 1.3963 140 2.4435 0.20 .0035 0.70 .0122 20' .0058 1 .3665 1 .4137 1 2.4609 1 .0037 1 .0124 21' .0061 2 .3840 2 .4312 2 2.4784 2 .0038 2 .0126 22' .0064 3 .4014 3 .4486 3 2.4958 3 .0040 3 .0127 23' .0067 4 .4189 4 .4661 4 2.5133 4 .0042 4 .0129 24' .0070 25 .4363 85 1.4835 145 2.5307 .25 .0044 .75 .0131 25' 0073 6 .4538 6 1.5010 6 2.5482 6 .0045 6 .0133 26' .0076 7 .4712 7 1.5184 7 2.5656 7 .0047 7 .0134 27' .0079 8 .4887 8 1.5359 8 2.5831 8 .0049 8 .0136 28' .0081 9 .5061 9 1.5533 9 2.6005 9 .0051 9 .0138 29' 0084 30 .5236 90 1.5708 150 2.6180 0.30 .0052 0.80 .0140 30' .0087 1 .5411 1 .5882 1 2.6354 1 .0054 1 .0141 31' .0090 2 .5585 2 1.6057 2 2.6529 2 .0056 2 0143 32' .0093 3 .5760 3 1.6232 3 2.6704 3 .0058 3 .0145 33' .0096 4 .5934 4 1.6406 4 2.6878 4 .0059 4 .0147 34' .0099 35 .6109 95 1.6581 155 2.7053 35 .0061 .85 .0148 35' .0102 6 .6283 6 1.6755 6 2.7227 6 .0063 6 .0150 36' .0105 7 .6458 7 1.6930 7 2.7402 7 .0065 7 .0152 37' .0108 8 .6632 8 1.7104 8 2.7576 8 .0066 8 .0154 38' .0111 9 .6807 9 1.7279 9 2.7751 9 .0068 9 .0155 39' .0113 40 .6981 100 1.7453 160 2.7925 0.40 .0070 0.90 .0157 40' .0116 1 .7156 1 1.7628 1 2.8100 1 .0072 1 .0159 41' .0119 2 .7330 2 1.7802 2 2.8274 2 .0073 2 .0161 42' .0122 3 .7505 3 1.7977 3 2.8449 3 .0075 3 .0162 43' .0125 4 .7679 4 1.8151 4 2.8623 4 .0077 4 .0164 44' .0128 45 .7854 105 1.8326 165 2.8798 .45 .0079 .95 .0166 45' .0131 6 .8029 6 1.8500 6 2.8972 6 .0080 6 .0168 46' .0134 7 .8203 7 1.8675 7 2.9147 7 .0082 7 .0169 47' .0137 8 .8378 8 1.8850 8 2.9322 8 .0084 8 .0171 48' .0140 9 .8552 9 1.9024 9 2.9496 9 .0086 9 .0173 49' .0143 50 .8727 110 1.9199 170 2.9671 0.50 .0087 1.00 .0175 50' .0145 1 .8901 1 1.9373 1 2.9845 51' 0148 2 .9076 2 1.9548 2 3.0020 52' .0151 3 .9250 3 1.9722 3 3.0194 53' 0154 4 .9425 4 1.9897 4 3.0369 54' .0157 55 .9599 115 2.0071 175 3.0543 55' .0160 6 .9774 6 2.0246 6 3.0718 56' 0163 7 .9948 7 2.0420 7 3.0892 57' .0166 8 1.0123 8 2.0595 8 3.1067 58' 0169 9 1.0297 9 2.0769 9 3.1241 59' .0172 60 1.0472 120 2.0944 180 3.1416 60' .0175 Arc 1 = 0.0174533 Arc 1' = 0.000290888 Arc 1" = 0.00000484814 1 radian - 57.295780 = 57 17'.7468 - 57 17' 44".806 MATHEMATICAL TABLES RADIANS EXPRESSED IN DEGREES 45 0.01 057 .64 36 67 1.27 72 77 1 90 108.86 2.53 144.% Interpolation 2 1.15 .65 37.24 8 73.34 1 109.43 4 145.53 .0002 0.01 3 1.72 6 37.82 9 73.91 2 110.01 2.55 146MO 04 .02 4 2.29 7 38.39 1.30 74.48 3 1KP.58 6 146.68 06 .03 .05 2.86 8 38.96 1 75.06 4 111.15 7 147.25 08 .05 6 3.44 9 39.53 2 75.63 1.95 111.73 8 147 .82 .0010 0.06 7 4.01 .70 40.1 1 3 76.20 6 112.30 9 148.40 12 .07 8 4.58 1 40.68 4 76.78 7 112.87 2.60 148.97 14 .08 9 5. 16 2 41.25 1.35 77.35 8 113.45 149.54 16 .09 .10 5.73 3 41.83 6 77.92 9 1I4.02 2 150. 11 18 .10 1 6.30 4 42.40 7 78.50 2.00 114.59 3 I50.69 .0020 0.ll 2 6.88 .75 42.97 8 79.07 1 115M6 4 151.26 22 .13 3 7.45 6 43.54 9 79.64 2 115.74 2.65 15P.83 24 .14 4 8.02 7 44. 12 1.40 80.21 3 116.31 6 152.41 26 .15 .15 8.59 8 44.69 1 80.79 4 116.88 7 152.98 28 .16 6 9. 17 9 45.26 2 81.36 2.05 1!7.46 8 153.55 .0030 0.17 7 9.74 .80 45.84 3 81.93 6 118.03 9 154. 13 32 .18 8 10.31 1 46.41 4 82.51 7 118.60 2.70 154.70 34 .19 9 10.89 2 46.98 1.45 83.08 8 119.18 1 155.27 36 .21 .20 1I.46 3 47.56 6 83.65 9 119.75 2 155.84 38 .22 1 12.03 4 48. 13 7 84.22 2.10 120.32 3 156.42 .0040 0.23 2 12.61 .85 48.70 8 84.80 1 120.89 4 156.99 42 .24 3 13.18 6 49.27 9 85.37 2 121 .47 2.75 157 .56 44 .25 4 13.75 7 49.85 1.50 85.94 3 122.04 6 158.14 46 .26 .25 14.32 8 50.42 1 86.52 4 122.61 7 158.7I 48 .28 6 14.90 9 50.99 2 87.09 2.15 123M9 8 159.28 .0050 0.29 7 15.47 .90 5J.57 3 87.66 6 123.76 9 159.86 52 .30 8 16.04 1 52.14 4 88.24 7 124.33 2.80 160.43 54 .31 9 16.62 2 52.71 1.55 88.81 8 124.90 1 161.00 56 .32 .30 17.19 3 53.29 6 89.38 9 125.48 2 16I.57 58 .33 1 17J6 4 53.86 7 89.95 2.20 126.05 3 162. 15 .0060 0.34 2 18.33 .95 54.43 8 90.53 11 126.62 4 162 .72 62 .36 3 18.91 6 55.00 9 91.10 127.20 2.85 163.29 64 .37 4 19.48 7 55.58 1.60 91.67 3 127.77 6 163.87 66 .38 .35 20.05 8 56. 15 1 92.25 4 128.34 7 164.44 68 .39 6 20.63 9 56.72 2 92.82 2.25 128.92 8 165.01 .0070 0.40 7 21.20 1.00 57.30 3 93039 6 129.49 9 165.58 72 .41 8 21.77 1 57.87 4 93.97 7 130.06 2.90 166M6 74 .42 9 22.35 2 58.44 1.65 94.54 8 130.6? 1 166.73 76 .44 .40 22.92 3 59.01 6 95. 11 9 131.21 2 167.30 78 .45 1 23.49 4 59.59 7 95.68 2.30 131.78 3 167.88 .0080 0.46 2 24.06 1.05 60. 16 8 96.26 1 132.35 4 168.45 82 .47 3 24.64 6 60.73 9 96.83 2 132.93 2.95 169.02 84 .48 4 25.21 7 61.31 1.70 97.40 3 133.50 6 169.60 86 .49 .45 25.78 8 61.88 1 97.98 4 134.07 7 170. 17 88 .50 6 26.36 9 62.45 2 98.55 2.35 134.65 8 170.74 .0090 0.52 7 26.93 1.10 63.03 3 99. 12 6 135.22 9 171.31 92 .53 8 27.50 1 63.60 4 99.69 7 135.79 3.00 17P.89 94 .54 9 28.07 2 64. 17 1.75 100.27 8 136.36 172.46 96 .55 .60 28.65 3 64.74 6 100.84 9 136.94 1 173.03 98 .56 | 29.22 4 65.32 7 10I.41 2.40 137j51 3 173.61 2 29079 1.15 65.89 8 10P.99 1 138.08 4 174. 18 Multiples of v 3 30.37 6 66.46 9 102.56 2 I38.66 3.05 174J5 4 30.94 7 67.04 1.80 103.13 3 139.23 6 175.33 1 3.1416 180 .55 31.51 8 67.61 1 103.71 4 139.80 7 175.90 2 6.2832 360 6 32.09 9 68. 18 2 104.28 2.45 140.37 8 176.47 3 9.4248 540 7 32.66 1.20 68.75 3 104.85 6 140.95 9 177.04 4 12.5664 720 8 33.23 I 69.33 4 105.42 7 141.52 3.10 177.62 5 15.7080 900 9 33.80 2 69.90 1.85 106.00 8 142.09 1 178. 19 6 18.8496 1080 .60 34.38 3 70.47 6 106.57 9 142.67 2 178.76 7 21.9911 1260 1 34.95 4 71.05 7 107. 14 2.50 143.24 3 179.34 8 25.1327 1440 2 35.52 1.25 71.62 8 107.72 1 143.81 V 4 179.91 9 28.2743 1620 3 36. 10 6 72. 19 9 108.29 2 144.39 3.15 180.48 10 31.4159 1800 46 MATHEMATICAL TABLES NATURAL SINES AND COSINES Natural Sines at intervals of 0.l, or 6'. (For 10' intervals, see pp. 52-56) M o o o B o o . P =^6o (60 (120 (180 (240 (300 (360 (420 (480 (540 1* 0.0000 90 0.0000 0017 0035 0052 0070 0087 0105 0122 0140 0157 0175 89 17 1 0175 0192 0209 0227 0244 0262 0279 0297 0314 0332 0349 88 17 2 0349 0366 0384 0401 0419 0436 0454 0471 0488 0506 0523 87 17 3 0523 0541 0558 0576 0593 0610 0628 0645 0663 0680 0698 86 17 4 0698 0715 0732 0750 0767 0785 0802 0819 0837 0854 0.0872 85 17 5 0.0872 0889 0906 0924 0941 0958 0976 0993 1011 1028 1045 84 17 6 1045 1063 1080 1097 1115 1132 1149 1167 1184 1201 1219 83 17 7 1219 1236 1253 1271 1288 1305 1323 1340 1357 1374 1392 82 17 8 1392 1409 1426 1444 1461 1478 1495 1513 1530 1547 1564 81 17 9 1564 1582 1599 1616 1633 1650 1668 1685 1702 '1719 0.1736 80 17 10 0.1736 1754 1771 1788 1805 1822 1840 1857 1874 1891 1908 79 17 11 1908 1925 1942 1959 1977 1994 2011 2028 2045 2062 2079 78 17 12 2079 2096 2113 2130 2147 2164 2181 2198 2215 2233 2250 77 17 13 2250 2267 2284 2300 2317 2334 2351 2368 2385 2402 2419 76 17 14 2419 2436 2453 2470 2487 2504 2521 2538 2554 2571 0.2588 75 17 15 0.2588 2605 2622 2639 2656 2672 2689 2706 2723 2740 2756 74 17 16 2756 2773 2790 2807 2823 2840 2857 2874 2890 2907 2924 73 17 17 2924 2940 2957 2974 2990 3007 3024 3040 3057 3074 3090 72 17 18 3090 3107 3123 3140 3156 3173 3190 3206 3223 3239 3256 71 17 19 3256 3272 3289 3305 3322 3338 3355 3371 3387 3404 0.3420 70 16 20 0.3420 3437 3453 3469 3486 3502 3518 3535 3551 3567 3584 69 16 21 3584 3600 3616 3633 3649 3665 3681 3697 3714 3730 3746 68 16 22 3746 3762 3778 3795 3811 3827 3843 3859 3875 3891 3907 67 16 23 3907 3923 3939 3955 3971 3987 4003 4019 4035 4051 4067 66 16 24 4067 4083 4099 4115 4131 4147 4163 4179 4195 4210 0.4226 65 16 25 0.4226 4242 4258 4274 4289 4305 4321 4337 4352 4368 4384 64 16 26 4384 4399 4415 4431 4446 4462 4478 4493 4509 4524 4540 63 16 27 4540 4555 4571 4586 4602 4617 4633 4648 4664 4679 4695 62 16 28 4695 4710 4726 4741 4756 4772 4787 4802 4818 4833 4848 61 15 29 4848 4863 4879 4894 4909 4924 4939 4955 4970 4985 0.5000 60 15 30 0.5000 5015 5030 5045 5060 5075 5090 5105 5120 5135 5150 59 15 31 5150 5165 5180 5195 5210 5225 5240 5255 5270 5284 5299 58 15 32 5299 5314 5329 5344 5358 5373 5388 5402 5417 5432 5446 57 15 33 5446 5461 5476 5490 5505 5519 5534 5548 5563 5577 5592 56 15 34 5592 5606 5621 5635 5650 5664 5678 5693 5707 5721 0.5736 55 14 35 0.5736 5750 5764 5779 5793 5807 5821 5835 5850 5864 5878 54 14 36 5878 5892 5906 5920 5934 5948 5962 5976 5990 6004 6018 53 14 37 6018 6032 6046 6060 6074 6088 6101 6115 6129 6143 6157 52 14 38 6157 6170 6184 6198 6211 6225 6239 6252 6266 6280 6293 51 14 39 6293 6307 6320 6334 6347 6361 6374 6388 6401 6414 0.6428 50 13 40 0.6428 6441 6455 6468 6481 6494 6508 6521 6534 6547 6561 49 13 41 6561 6574 6587 6600 6613 6626 6639 6652 6665 6678 6691 48 13 42 6691 6704 6717 6730 6743 6756 6769 6782 6794 6807 6820 47 13 43 6820 6833 6845 6858 6871 6884 6896 6909 6921 6934 6947 46 13 44 6947 6959 6972 6984 6997 7009 7022 7034 7046 7059 0.7071 45 12 45 0.7071 =(540 (480 (420 (360 (300 (240 (180 (120 (60 (00 i (For graphs, see p. 174.) Natural Cosines MATHEMATICAL TABLES 47 NATURAL SINES AND COSINES (continued) Natural Sines at intervals of 0.l, or 6'. (For 10' intervals, see pp. 52-56) M o .l 2 03 4 5 6 07 03 09 *d a =(0 / ) (60 (120 (180 (240 (300 (360 (420 (480 (540 <* 0.7071 45 45 0.7071 7083 7096 7108 7120 7133 7145 7157 7169 7181 7193 44 12 46 7193 7206 7218 7230 7242 7254 7266 7278 7290 7302 7314 43 12 47 731 4 7325 7337 7349 7361 7373 7385 7396 7408 7420 7431 42 12 48 743 1 7443 7455 7466 7478 7490 7501 7513 7524 7536 7547 41 12 49 7547 7559 7570 7581 7593 7604 7615 7627 7638 7649 0.7660 40 11 50 0.7660 7672 7683 7694 7705 7716 7727 7738 7749 7760 7771 39 11 51 7771 7782 7793 7804 7815 7826 7837 7848 7859 7869 7880 38 11 52 788 7891 7902 7912 7923 7934 7944 7955 7965 7976 7986 37 11 53 7986 7997 8007 8018 8028 8039 8049 8059 8070 8080 8090 36 10 54 8090 8100 8111 8121 8131 8141 8151 8161 8171 8181 0.8192 35 10 55 0.8192 8202 8211 8221 8231 8241 8251 8261 8271 8281 8290 34 10 56 829 8300 8310 8320 8329 8339 8348 8358 8368 8377 8387 33 10 57 8387 8396 8406 8415 8425 8434 8443 8453 8462 8471 8480 32 9 58 848 8490 8499 8508 8517 8526 8536 8545 8554 8563 8572 31 9 59 8572 8581 8590 8599 8607 8616 8625 8634 8643 8652 0.8660 30 9 60 0.8660 8669 8678 8686 8695 8704 8712 8721 8729 8738 8746 29 9 61 8746 8755 8763 8771 8780 8788 8796 8805 8813 8821 8829 28 8 62 882 9 8838 8846 8854 8862 8870 8878 8886 8894 8902 8910 27 8 63 8910 8918 8926 8934 8942 8949 8957 8965 8973 8980 8988 26 8 64 8988 8996 9003 9011 9018 9026 9033 9041 9048 9056 0.9063 25 7 65 0.9063 9070 9078 9085 9092 9100 9107 9114 9121 9128 9135 24 7 66 913 5 9143 9150 9157 9164 9171 9178 9184 9191 9198 9205 23 7 67 9205 9212 9219 9225 9232 9239 9245 9252 9259 9265 9272 22 7 68 927 2 9278 9285 9291 9298 9304 9311 9317 9323 9330 9336 21 6 69 9336 9342 9348 9354 9361 9367 9373 9379 9385 9391 0.9397 20 6 70 0.9397 9403 9409 9415 9421 9426 9432 9438 9444 9449 9455 19 6 71 945 5 9461 9466 9472 9478 9483 9489 9494 9500 9505 9511 18 6 72 951 1 9516 9521 9527 9532 9537 9542 9548 9553 9558 9563 17 5 73 . 9563 9568 9573 9578 9583 9588 9593 9598 9603 9608 9613 16 5 74 9613 9617 9622 9627 9632 9636 9641 9646 9650 9655 0.9659 15 5 75 0.9659 9664 9668 9673 9677 9681 9686 9690 9694 9699 9703 14 4 76 970 3 9707 9711 9715 9720 9724 9728 9732 9736 9740 9744 13 4 77 9744 9748 9751 9755 9759 9763 9767 9770 9774 9778 9781 12 4 78 978 1 9785 9789 9792 97% 9799 9803 9806 9810 9813 9816 11 3 79 9816 9820 9823 9826 9829 9833 9836 9839 9842 9845 0.9848 10 3 80 0.9848 9851 9854 9857 9860 9863 9866 9869 9871 9874 9877 9 3 81 9877 9880 9882 9885 9888 9890 9893 9895 9898 9900 9903 8 3 82 990 3 9905 9907 9910 9912 9914 9917 9919 9921 9923 9925 7 2 83 992 5 9928 9930 9932 9934 9936 9938 9940 9942 9943 9945 6 2 84 9945 9947 9949 9951 9952 9954 9956 9957 9959 9960 0.9962 5 2 85 0.9962 9963 9965 9966 9968 9969 9971 9972 9973 9974 9976 4 1 86 997 6 9977 9978 9979 9980 9981 9982 9983 9984 9985 9986 3 1 87 9986 9987 9988 9989 9990 9990 9991 9992 9993 9993 9994 2 1 88 999 4 9995 9995 9996 9996 9997 9997 9997 9998 9998 0.9998 1 89 0.9998 9999 9999 9999 9999 0000 0000 0000 0000 0000 1. 0000 90 1.0000 = (540 (480 (420 (360 (300 (240 (180 (120 (60 (00 $ Q Natural Cosines 48 MATHEMATICAL TABLES NATURAL TANGENTS AND COTANGENTS Natural Tangents at intervals of 0.l, or 6'. (For 10' intervals, see pp. 52-56) ff .0 M 2 3 4 05 0( j 07 03 9 * Q -coo (60 (12') (18') (24') (30') (360 (420 (48') (54') IS 0.0000 90 0.0000 0017 0035 0052 0070 0087 0105 0122 0140 0157 0175 89 17 1 0175 0192 0209 0227 0244 0262 0279 0297 0314 0332 0349 88 17 2 0349 0367 0384 0402 0419 0437 0454 0472 0489 0507 0524 87 17 3 0524 0542 0559 0577 0594 0612 0629 0647 0664 0682 0699 86 18 4 0699 0717 0734 0752 0769 0787 0805 0822 0840 0857 0.0875 85 18 5 0.0875 0892 0910 0928 0945 0963 0981 0998 1016 1033 1051 84 18 6 1051 1069 1086 1104 1122 1139 1157 1175 1192 1210 1228 83 18 7 1228 1246 1263 1281 1299 1317 1334 1352 1370 1388 1405 82 18 8 1405 1423 1441 1459 1477 1495 1512 1530 1548 1566 1584 81 18 9 1584 1602 1620 1638 1655 1673 1691 1709 1727 1745 0.1763 80 18 10 0.1763 1781 1799 1817 1835 1853 1871 1890 1908 1926 1944 79 18 It 1944 1962 1980 1998 2016 2035 2053 2071 2089 2107 2126 78 18 12 2126 2144 2162 2180 2199 2217 2235 2254 2272 2290 2309 77 18 13 2309 2327 2345 2364 2382 2401 2419 2438 2456 2475 2493 76 18 14 2493 2512 2530 2549 2568 2586 2605 2623 2642 2661 0.2679 75 19 15 0.2679 2698 2717 2736 2754 2773 2792 2811 2830 2849 2867 74 19 16 2867 2886 2905 2924 2943 2962 2981 3000 3019 3038 3057 73 19 17 3057 3076 3096 3115 3134 3153 3172 3191 3211 3230 3249 72 19 18 3249 3269 3288 3307 3327 3346 3365 3385 3404 3424 3443 71 19 19 3443 3463 3482 3502 3522 3541 3561 3581 3600 3620 0.3640 70 20 20 0.3640 3659 3679 3699 3719 3739 3759 3779 3799 3819 3839 69 20 21 3839 3859 3879 3899 3919 3939 3959 3979 4000 4020 4040 68 20 22 4040 4061 4081 4101 4122 4142 4163 4183 4204 4224 4245 67 21 23 4245 4265 4286 4307 4327 4348 4369 4390 4411 4431 4452 66 21 24 4452 4473 4494 4515 4536 4557 4578 4599 4621 4642 0.4663 65 21 25 0.4663 4684 4706 4727 4748 4770 4791 4813 4834 4856 4877 64 21 26 4877 4899 4921 4942 4964 4986 5008 5029 5051 5073 5095 63 22 27 5095 5117 5139 5161 5184 5206 5228 5250 5272 5295 5317 62 22 28 5317 5340 5362 5384 5407 5430 5452 5475 5498 5520 5543 61. 23 29 5543 5566 5589 5612 5635 5658 5681 5704 5727 5750 0.5774 60 23 30 0.5774 5797 5820 5844 5867 5890 5914 5938 5961 5985 6009 59 24 31 6009 6032 6056 6080 6104 6128 6152 6170 6200 6224 6249 58 24 32 6249 6273 6297 6322 6346 6371 6395 6420 6445 6469 6494 57 25 33 6494 6519 6544 6569 6594 6619 6644 6669 6694 6720 6745 56 25 34 6745 6771 6796 6822 6847 6873 6899 6924 6950 6976 0.7002 55 26 35 0.7002 7028 7054 7080 7107 7133 7159 7186 7212 7239 7265 54 26 36 7265 7292 7319 7346 7373 7400 7427 7454 7481 7508 7536 53 27 37 7536 7563 7590 7618 7646 7673 7701 7729 7757 7785 7813 52 28 38 7813 7841 7869 7898 7926 7954 7983 8012 8040 8069 8098 51 28 39 8098 8127 8156 8185 8214 8243 8273 8302 8332 8361 0.8391 50 29 40 0.8391 8421 8451 8481 8511 8541 8571 8601 8632 8662 8693 49 30 41 8693 8724 8754 8785 8816 8847 8878 8910 8941 8972 9004 48 31 42 9004 9036 9067 9099 9131 9163 9195 9228 9260 9293 9325 47 32 43 9325 9358 9391 9424 9457 9490 9523 9556 9590 9623 0.9657 46 33 44 0.9657 9691 9725 9759 9793 9827 9861 9896 9930 9965 1.0000 45 34 45 1.0000 *(54 9 ') (480 (420 (36') (300 (240 (18') (120 (60 (00 1 (For graphs, see p. 174.) Natural Cotangents MATHEMATICAL TABLES 49 NATURAL TANGENTS AND COTANGENTS (continued) Natural Tangents at intervals of 0. 1, or 6'. (For 10' intervals, see pp. 52-56) i a=Y(V ) (60 (120 (180 (240 (300 (360 (420 (480 (540 diff! 1.0000 45 45 1.0000 0035 0070 0105 0141 0176 0212 0247 0283 0319 0355 44 35 46 035 5 0392 0428 0464 0501 0538 0575 0612 0649 0686 0724 43 37 47 072 4 0761 0799 0837 0875 0913 0951 0990 1028 1067 1106 42 38 48 1106 1145 1184 1224 1263 1303 1343 1383 1423 1463 1504 41 40 49 1504 1544 1585 1626 1667 1708 1750 1792 1833 18751.1918 40 41 50 1.1918 1960 2002 2045 2088 2131 2174 2218 2261 2305 2349 39 43 51 234 9 2393 2437 2482 2527 2572 2617 2662 2708 2753 2799 38 45 52 2799 2846 2892 2938 2985 3032 3079 3127 3175 3222 3270 37 47 53 327 3319 3367 3416 3465 3514 3564 3613 3663 3713 3764 36 49 54 3764 3814 3865 3916 3968 4019 4071 4124 4176 42291.4281 35 52 55 1 .4281 4335 4388 4442 44% 4550 4605 4659 4715 4770 4826 34 55 56 4826 4882 4938 4994 5051 5108 5166 5224 5282 5340 5399 33 57 57 539 9 5458 5517 5577 5637 5697 5757 5818 5880 5941 6003 32 60 58 6003 6066 6128 6191 6255 6319 6383 6447 6512 6577 6643 31 64 59 1.6643 6709 6775 6842 6909 6977 7045 7113 7182 7251 1.7321 30 67 60 1.732 1.739 1.746 1.753 1.760 1.76} 1.775 1.782 1.789 1.797 1.804 29 7 61 1.80 4 1.811 1.819 1.827 1.834 1.842 1.849 1.857 1.865 1.873 1.881 28 8 62 1.88 1 1.889 1.897 1.905 1.913 1.921 1.929 1.937 1.946 1.954 1.963 27 8 63 1.963 1.971 1.980 1.988 1.997 2.006 2.014 2023 2.032 2.041 2.050 26 9 64 2.050 2.059 2.069 2.078 2.087 2.097 2.1062.116 2.125 2.135 2.145 25 9 65 2.145 2.154 2.164 2.174 2.184 2.194 2.204 2.215 2.225 2.236 2.246 24 10 66 2.24 6 2.257 2.267 2.278 2.289 2.300 2.311 2.322 2.333 2.344 2.356 23 11 67 2.356 2.367 2.379 2.391 2.402 2.414 2.426 2.438 2.450 2.463 2.475 22 12 68 2.47 5 2.488 2.500 2.513 2.526 2.539 2.552 2.565 2.578 2.592 2.605 21 13 69 2.605 2.619 2.633 2.646 2.660 2.675 2.689 2.703 2.718 2.733 2.747 20 14 70 2.747 2.762 2.778 2.793 2.808 2.824 2.840 2.856 2.872 2.888 2.904 19 16 71 2.904 2.921 2.937 2.954 2.971 2.989 3.006 3.024 3.042 3.060 3.078 18 17 72 3.07 8 3.096 3.115 3.133 3.152 3.172 3.191 3.211 3.230 3.251 3.271 17 19 73 3.271 3.291 3.312 3.333 3.354 3.376 3.398 3.420 3.442 3.465 3.487 16 22 74 3.487 3.511 3.534 3.558 3.582 3.606 3.630 3.655 3.681 3.706 3.732* 15 24 75 3.732 3.758 3.785 3.812 3.839 3.867 3.895 3.923 3.952 3.981 4.011 14 28 76 4.01 1 4.041 4.071 4.102 4.134 4.165 4.198 4.230 4.264 4.297 4.331 13 32 77 4.331 4.366 4.402 4.437 4.474 4.511 4.548 4.586 4.625 4.665 4.705 12 37 78 4.70 5 4.745 4.787 4.829 4.872 4.915 4.959 5.005 5.050 5.097 5.145 11 44 79 5.145 5.193 5.242 5.292 5.343 5.396 5.449 5.503 5.558 5.614 5:671 10 53 80 5,671 5.730 5.789 5.850 5.912 5.976 6.041 6.107 6.174 6.243 6.314 9 81 6.314 6.386 6.460 6.535 6.612 6.691 6.772 6 855 6.940 7.026 7.115 8 82 7.11 5 7.207 7.300 7.396 7.495 7.596 7.700 7.806 7.916 8.028 8.144 7 83 8.14 4 8.264 8.386 8.513 8.643 8.777 8.915 9.058 9.205 9.357 9.514 6 84 9.514 9.677 9.845 10.02 10.20 10.39 10.58 10.78 10.99 11.20 11.43 5 85 11.43 11.66 11.91 12.16 12.43 12.71 13.00 1330 13.62 13.95 14.30 4 86 14.3 [) 14.67 15.06 15.46 15.89 16.35 16.83 17.34 17.89 18.46 19.08 3 87 19.a 8 19.74 20.45 21.20 22.02 22.90 23.86 24^90 26.03 27.27 28.64 2 88 28.64 30.14 31.82 33.69 35.80 38.19 40.92 44.07 47.74 52.08 57.29 1 89 57.29 63.66 71.62 81.85 95.49 114.6 143.2 191.0 286.5 573.0 oo 90 00 =(540 (480 (420 (360 (300 (240 (180 (120 (60 (0*0 i Natural Cotangents 50 MATHEMATICAL TABLES NATURAL SECANTS AND COSECANTS Natural Secants at intervals of 0. 1, or 6'. (For 10' intervals, see pp. 52-56) i -(V (60* (120 (180 (240 (3V) (360 (420 (480 (540 Avg. diff. 1.0000 90 1.0001 3 0000 0000 0000 0000 0000 0001 0001 0001 0001 0002 89 1 000 I 0002 0002 0003 0003 0003 0004 0004 0005 0006 0006 88 2 000 i 0007 0007 0008 0009 0010 0010 0011 0012 0013 0014 87 3 001' \ 0015 0016 0017 0018 0019 0020 0021 0022 0023 0024 86 1 4 002' I 0026 0027 0028 0030 0031 0032 0034 0035 0037 1.0038 85 1 5 1.003 J 0040 0041 0043 0045 0046 0048 0050 0051 0053 0055 84 2 6 005. > 0057 0059 0061 0063 0065 0067 0069 0071 0073 0075 83 2 7 007. > 0077 0079 0082 0084 0086 0089 0091 0093 0096 0098 82 2 8 009* ) 0101 0103 0106 0108 0111 0114 0116 0119 0122 0125 81 3 9 01 2f > 0127 0130 0133 0136 0139 0142 0145 0148 0151 1.0154 80 3 10 \ 0157 0161 0164 0167 0170 0174 0177 0180 0184 0187 79 3 11 018} ' 0191 0194 0198 0201 0205 0209 0212 0216 0220 0223 78 4 12 022: I 0227 0231 0235 0239 0243 0247 0251 0255 0259 0263 77 4 13 026: I 0267 0271 0276 0280 0284 0288 0293 0297 0302 0306 76 4 14 030* > 0311 0315 0320 0324 0329 0334 0338 0343 0348 1.0353 75 5 15 1 .035: I 0358 0363 0367 0372 0377 *0382 0388 0393 0398 0403 74 5 16 040: 5 0408 0413 0419 0424 0429 0435 0440 0446 0451 0457 73 5 17 0453 ' 0463 0468 0474 0480 0485 0491 0497 0503 0509 0515 72 6 18 051f 0521 0527 0533 0539 0545 0551 0557 0564 0570 0576 71 6 19 057* 0583 0589 0595 0602 0608 0615 0622 0628 0635 1.0642 70 7 20 1.064; ' 0649 0655 0662 0669 0676 0683 0690 0697 0704 0711 69 7 21 071 0719 0726 0733 0740 0748 0755 0763 0770 0778 0785 68 7 22 078f 0793 0801 0808 0816 0824 0832 0840 0848 0856 0864 67 8 23 0864 0872 0880 0888 0896 0904 0913 0921 0929 0938 0946 66 8 24 094* 0955 0963 0972 0981 0989 0998 1007 1016 1025 1.1034 65 9 25 1.103' f 1043 1052 1061 1070 1079 1089 1098 1107 1117 1126 64 9 26 112* > 1136 1145 1155 1164 1174 1184 1194 1203 1213 1223 63 10 27 1222 1233 1243 1253 1264 1274 1284 1294 1305 1315 1326 62 10 28 132* 1336 1347 1357 1368 1379 1390 1401 1412 1423 1434 61 11 29 1434 1445 1456 1467 1478 1490 1501 1512 1524 1535 1.1547 60 11 30 1.1543 ' 1559 1570 1582 1594 1606 1618 1630 1642 1654 1666 59 12 31 166* 1679 1691 1703 1716 1728 1741 1753 1766 1779 1792 58 13 32 179; 1805 1818 1831 1844 . 1857 1870 1883 1897 1910 1924 57 13 33 1924 1937 1951 1964 1978 1992 2006 2020 2034 2048 2062 56 14 34 206; 2076 2091 2105 2120 2134 2149 2163 2178 2193 1.2208 55 15 35 1.220* 2223 2238 2253 2268 2283 2299 2314 2329 2345 2361 54 15 36 2361 2376 2392 2408 2424 2440 245* 2472 2489 2505 2521 53 16 37 2521 2538 2554 2571 2588 2605 2622 2639 2656 2673 2690 52 17 38 269C 2708 2725 2742 2760 2778 2796 2813 2831 2849 2868 51 18 39 2866 2886 2904 2923 2941 2960 2978 2997 3016 3035 1.3054 60 19 40 1.3054 3073 3093 3112 3131 3151 3171 3190 3210 3230 3250 49 20 41 325C 3270 3291 3311 3331 3352 3373 3393 34 M 3435 3456 48 21 42 345* 3478 3499 3520 3542 3563 3585 3607 3629 3651 3673 47 22 43 3673 3696 3718 3741 3763 3786 3809 3832 3855 3878 3902 46 23 44 3902 3925 3949 3972 3996 4020 4044 4069 4093 4118 1.4142 45 24 45 1.4142 t , = (540 (480 (420 (360 (300 (240 (180 (120 (60 (00 Q (For graphs, see p. 174.) Natural Cosecants MATHEMATICAL TABLES 51 NATURAL SECANTS AND COSECANTS (continued) Natural Secants at intervals of 0.l, or 6'. (For 10' intervals, see pp. 52-56) .o .l .a .3 .4 .5 .6 .7 .8 .9 Avg. Q =(00 (60 (120 (180 (240 (300 (360 (420 (480 (540 diff. 1.4142 45 45 1.4142 4167 4192 4217 4242 4267 4293 4318 4344 4370 4396 44 25 46 4396 4422 4448 4474 4501 4527 4554 4581 4608 4635 4663 43 27 47 4663 4690 4718 4746 4774 4802 4830 4859 4887 4916 4945 42 28 48 4945 4974 5003 5032 5062 5092 5121 5151 5182 5212 5243 41 30 49 5243 5273 5304 5335 5366 5398 5429 5461 5493 5525 1.5557 40 31 60 1.5557 5590 5622 5655 5688 5721 5755 5788 5822 5856 5890 39 33 51 5890 5925 5959 5994 6029 6064 6099 6135 6171 6207 6243 38 35 52 6243 6279 6316 6353 6390 6427 6464 6502 6540 6578 6616 37 37 53 6616 6655 6694 6733 6772 6812 6852 6892 6932 6972 7013 36 40 54 7013 7054 7095 7137 7179 7221 7263 7305 7348 7391 1.7434 35 42 55 1.7434 7478 7522 7566 7610 7655 7700 7745 7791 7837 7883 34 45 56 7883 7929 7976 8023 8070 8118 8166 8214 8263 8312 8361 33 48 57 8361 8410 8460 8510 8561 8612 8663 8714 8766 8818 8871 32 51 58 8871 8924 8977 9031 9084 9139 9194 9249 9304 9360 1.9416 31 54 59 1.9416 9473 9530 9587 9645 9703 9762 9821 9880 9940 2.0000 30 58 60 2.00C 2.006 2.012 2.018 2.025 2.031 2.037 2.043 2.050 2.056 2.063 29 6 61 2.063 2.069 2.076 2.082 2.089 2.096 2.103 2.109 2.116 2.123 2.130 28 7 62 2.13C 2.137 2.144 2.151 2.158 2.166 2.173 2.180 2.188 2.195 2.203 27 7 63 2.203 2.210 2.218 2.226 2.233 2.241 2.249 2.257 2.265 2.273 2281 26 8 64 2.281 2.289 2.298 2.306 2.314 2.323 2.331 2.340 2349 2357 2366 25 8 65 2.36< 2375 2.384 2.393 2.402 2.411 2.421 2.430 2.439 2.449 2.459 24 9 66 2.45< 2.468 2.478 2.488 2.498 2.508 2.518 2.528 2.538 2.549 2.559 23 10 67 2.55< 2.570 2.581 2.591 2.602 2.613 2624 2.635 2.647 2.658 2.669 22 11 68 2.66' 2.681 2.693 2.705 2.716 2.729 2.741 2.753 2.765 2.778 2.790 21 12 69 2.79( 2.803 2.816 2.829 2.842 2.855 2.869 2.882 2.896 2.910 2.924 20 13 70 2.92^ \ 2.938 2.952 2.967 2.981 2.996 3.011 3.026 3.041 3.056 3.072 19 15 71 3.07; 3.087 3.103 3.119 3.135 3.152 3.168 3.185 3.202 3.219 3.236 18 16 72 3.23( 3.254 3.271 3.289 3.307 3326 3.344 3.363 3.382 3.401 3.420 17 18 73 3.42C 3.440 3.460 3.480 3.500 3.521 3.542 3.563 3.584 3.606 3.628 16 21 74 3.62* I 3.650 3.673 3.695 3.719 3.742 3.766 3.790 3.814 3.839 3.864 15 24 75 3.86^ I 3.889 3.915 3.941 3.967 3.994 4.021 4.049 4.077 4.105 4.134 14 27 76 4.13^ 4.163 4.192 4.222 4.253 4.284 4.315 4.347 4379 4.412 4.445 13 31 77 4.44! 4.479 4.514 4.549 4.584 4.620 4.657 4.694 4.732 4.771 4.810 12 36 78 4.8H 1 4.850 4.890 4.931 4.973 5.016 5.059 5.103 5.148 5.194 5.241 11 43 79 5.24 5.288 5337 5.386 5.436 5.487 5.540 5.593 5.647 5.702 5.759 10 52 80 5.75 C > 51816 5.875 5.935 5.996 6.059 6.123 6.188 6.255 6.323 6392 9 81 6.39; ! 6.464 6.537 6.611 6.687 6.765 6.845 6.927 7.011 7.097 7.185 8 82 7.18f 7.276 7.368 7.463 7.561 7.661 7.764 7.870 7.979 8.091 8.206 7 83 8.2W 8.324 8.446 8.571 8.700 8.834 8.971 9.113 9.259 9.411 9.567 6 84 9.563 9.728 9.895 10.07 1025 10.43 10.63 10.83 11.03 11.25 11.47 5 85 11.42 ' 11.71 11.95 12.20 12.47 12.75 13.03 13.34 13.65 13.99 1434 4 86 14.3' \ 14.70 15.09 15.50 15.93' 16.38 16.86 17.37 17.91 18.49 19.11 3 87 19.1 19.77 20.47 21.23 22,04 22.93 23.88 24.92 26.05 27.29 28.65 2 88 28.6! 30.16 31.84 33.71 35.81 38.20 40.93 44.08 47.75 52.09 57.30 89 573( ) 63.66 71.62 81.85 95.49 114.6 143.2 191.0 286.5 573.0 00 90 oo .9 .8 .7 .6 .5 M =(540 (480 (420 (360 (300 (240 (180 (120 (60 (oo a Natural Cosecants 52 MATHEMATICAL TABLES TRIGONOMETRIC FUNCTIONS (at intervals of 10') Annex -10 in columns marked *. (For O.l intervals, see pp. 46-51) De- grees Ra- dians Sines Cosines Tangents Cotangents Nat. Log.* Nat. Log.* Nat. Log.* Nat. Log. (XX 0.0000 .0000 t.OOOO 0.0000 .0000 CO 00 1.5708 90 00* 10 00029 .0029 7.4637 1.0000 .0000 .0029 7.4637 343.77 2.5363 1.5679 50 20 00058 .0058 .7648 1.0000 .0000 .0058 .7648 171.89 .2352 1.5650 40 30 00087 .0087 .9408 1.0000 .0000 .0087 .9409 114.59 .0591 1.5621 30 40 0.0116 .0116 8.0658 0.9999 .0000 .0116 8.0658 85.940 1.9342 1.5592 20 50 0.0145 .0145 .1627 .9999 .0000 .0145 .1627 68.750 .8373 1.5563 10 1 00' 0.0175 .0175 8.2419 .9998 9.9999 .0175 8.2419 57.290 1.7581 1.5533 89 00' 10 0.0204 .0204 .3088 .9998 .9999 .0204 .3089 49.104 .6911 1.5504 50 20 0.0233 .0233 .3668 .9997 .9999 .0233 .3669 42.964 .6331 1.5475 40 30 0.0262 .0262 .4179 .9997 .9999 .0262 .4181 38.188 .5819 1.5446 30 40 0.0291 .0291 .4637 .9996 .9998 .0291 .4638 34.368 .5362 1.5417 20 50 0.0320 .0320 .5050 .9995 .9998 .0320 .5053 31.242 .4947 1.5388 10 2 (XX 0.0349 .0349 8.5428 .9994 9.9997 .0349 8.5431 28.636 1.4569 1.5359 88 00' 10 0.0378 .0378 .5776 .9993 .9997 .0378 .5779 26.432 .4221 1.5330 50 20 0.0407 .0407 .6097 .9992 .9996 .0407 .6101 24.542 .3899 1.5301 40 30 0.0436 .0436 .6397 .9990 .9996 .0437 .6401 22.904 .3599 1.5272 30 40 0.0465 .0465 .6677 .9989 .9995 .0466 .6682 21.470 .3318 1 .5243 20 50 0.0495 .0494 .6940 .9988 .9995 .0495 .6945 20.206 .3055 1.5213 10 3 (XX 0.0524 .0523 8.7188 .9986 9.9994 .0524 8.7194 19.081 1.2806 1.5184 87 00' 10 0.0553 .0552 .7423 .9985 .9993 .0553 .7429 18.075 .2571 1.5155 50 20 0.0582 .0581 .7645 .9983 .9993 .0582 .7652 17.169 .2348 1.5126 40 30 0.061 1 .0610 .7857 .9981 .9992 .0612 .7865 16.350 .2135 1.5097 30 40 0.0640 .0640 .8059 .9980 .9991 .0641 .8067 15.605 .1933 1.5068 20 50 0.0669 .0669 .8251 .9978 .9990 .0670 .8261 14.924 .1739 1.5039 10 4 (XX 0.0698 .0698 8.8436 .9976 9.9989 .0699 8.8446 14.301 1.1554 1.5010 86 00 10 0.0727 .0727 .8613 .9974 .9989 .0729 .8624 13.727 .1376 1.4981 50 20 0.0756 .0756 .8783 .9971 .9988 .0758 .8795 13.197 .1205 1.4952 40 30 0.0785 .0785 .8946 .9969 .9987 .0787 .8960 12.706 .1040 1.4923 30 40 0.0814 .0814 .9104 .9967 .9986 .0816 .9118 12.251 .0882 1.4893 20 50 0.0844 .0843 .9256 ,9964 .9985 .0846 .9272 11.826 .0728 1.4864 10 5 (XX 0.0873 .0872 8.9403 .9962 9.9983 .0875 8.9420 11.430 1.0580 1.4835 85 00' 10 0.0902 .0901 .9545 .9959 .9982 .0904 .9563 11.059 .0437 1.4806 50 20 0.0931 .0929 .9682 .9957 .9981 .0934 .9701 10.712 .0299 1.4777 40 30 0.0960 .0958 .9816 .9954 .9980 .0963 .9836 10.385 .0164 1.4748 30 40 0.0989 .0987 .9945 .9951 .9979 .0992 .9966 10.078 .0034 1.4719 ' 20 50 0.1018 .1016 9.0070 .9948 .9977 .1022 9.0093 9.7882 0.9907 1.4690 10 6 00' 0.1047 .1045 9.0192 .9945 9.9976 .1051 9.0216 9.5144 0.9784 1.4661 84 00' 10 0.1076 .1074 .0311 .9942 .9975 .1080 .0336 9.2553 .9664 1.4632 50 20 0.1105 .1103 .0426 .9939 .9973 .1110 .0453 9.0098 .9547 1.4603 40 30 0.1134 .1132 .0539 .9936 .9972 .1139 .0567 8.7769 .9433 1.4574 30 40 0.1164 .1161 .0648 .9932 .9971 .1169 .0678 8.5555 .9322 1.4544 20 50 0.1193 .1190 .0755 .9929 .9969 .1198 .0786 8.3450 .9214 1.4515 10 7 00' 0.1222 .1219 9.0859 .9925 9.9968 .1228 9.0891 8.1443 0.9109 1.4486 83 00' 10 0.1251 .1248 .0961 .9922 .9966 .1257 .0995 7.9530 .9005 1.4457 50 20 0.1280 .1276 .1060 .9918 .9964 .1287 .1096 7.7704 .8904 1.4428 40 30 0.1309 .1305 .1157 .9914 .9963 .1317 .1194 7.5958 .8806 1.4399 30 40 a 1338 .1334 .1252 .991 1 .9961 .1346 .1291 7.4287 .8709 1.4370 20 50 0.1367 .1363 .1345 .9907 .9959 .1376 .1385 7.2687 .8615 1.4341 10 8 00' 0.1396 .1392 9.1436 .9903 9.9958 .1405 9.1478 7.1154 0.8522 1.4312 82 00' 10 0.1425 .1421 .1525 .9899 .9956 .1435 .1569 6.9682 .8431 1.4283 50 20 0.1454 .1449 .1612 .9894 .9954 .1465 .1658 6.8269 .8342 1.4254 40 30 0.1484 .1478 .1697 .9890 .9952 .1495 .1745 6.6912 .8255 1.4224 30 40 0.1513 .1507 .1781 .9886 .9950 .1524 .1831 6.5606 .8169 1.4195 20 50 0.1542 .1536 .1863 .9881 .9948 .1554 .1915 6.4348 .8085 1.4166 10 9 (XX 0.1571 .1564 9.1943 .9877 9.9946 .1584 9.1997 6.3138 0.8003 1.4137 81 00' Nat. Log.* Nat. Log.* Nat. Log.* Nat. Log. Cosines Sines Cotangents Tangents Ra- dians De- grees MATHEMATICAL TABLES 53 TRIGONOMETRIC FUNCTIONS (continued) Annex -10 in columns marked*. (For O.l intervals, see pp. 46-51) De- grees Ra- dians Sines Cosines Tangents Cotangent Nat. Log.* Nat. Log.* Nat. Log.* Nat. Log. 9 00' 0.1571 .1564 9.1943 .9877 9.9946 .1584 9.1997 6.3138 0.8003 1.4137 81" (XX kio 0.1600 .1593 .2022 .9872 .9944 .1614 .2078 6.1970 .7922 1.4108 50 20 0.1629 .1622 .2100 .9868 .9942 .1644 .2158 6.0844 .7842 1.4079 40 30 0.1658 .1650 .2176 .9863 .9940 .1673 .2236 5.9758 .7764 1.4050 30 40 0.1687 .1679 .2251 .9858 .9938 .1703 .2313 5.8708 .7687 1.4021 20 50 0.1716 .1708 .2324 .9853 .9936 .1733 2389 5.7694 .7611 1.3992 10 10 00' 0.1745 .1736 9.2397 .9848 9.9934 .1763 9.2463 5.6713 0.7537 1.3963 80 (XX 10 0.1774 .1765 .2468 .9843 .9931 .1793 2536 5.5764 .7464 1.3934 50 20 0.1804 .1794 .2538 .9838 .9929 .1823 2609 5.4845 .7391 1.3904 40 30 0.1833 .1822 .2606 .9833 .9927 .1853 2680 5.3955 .7320 1.3875 30 40 0.1862 .1851 .2674 .9827 .9924 .1883 2750 5.3093 .7250 1.3846 20 50 0.1891 .1880 .2740 .9822 .9922 .1914 2819 5.2257 .7181 1.3817 10 11 00' 0.1920 .1908 9.2806 .9816 9.9919 .1944 92887 5.1446 0.7113 1.3788 790(X 10 0.1949 .1937 .2870 .9811 .9917 .1974 2953 5.0658 .7047 1.3759 50 20 0.1978 .1965 .2934 .9805 .9914 .2004 .3020 4.9894 .6980 1.3730 40 30 0.2007 .1994 .2997 .9799 .9912 2035 .3085 4.9152 .6915 1.3701 30 40 0.2036 .2022 .3058 .9793 .9909 2065 .3149 4.8430 .6851 1.3672 20 50 0.2065 2051 .3119 .9787 .9907 2095 .3212 4.7729 .6788 1.3643 10 12 00' 0.2094 .2079 9.3179 .9781 9.9904 2126 9.3275 4.7046 0.6725 1.3614 78 00' 10 0.2123 .2108 .3238 .9775 .9901 2156 3336 4.6382 .6664 1.3584 50 20 0.2153 .2136 .3296 .9769 .9899 2186 .3397 4.5736 .6603 1.3555 40 30 0.2182 .2164 .3353 .9763 .9896 2217 .3458 4.5107 .6542 1.3526 30 40 0.2211 .2193 .3410 .9757 .9893 2247 .3517 4.4494 .6483 1.3497 20 50 0.2240 .2221 .3466 .9750 .9890 2278 .3576 4.3897 .6424 1.3468 10 13 00' 0.2269 .2250 9.3521 .9744 9.9887 2309 9.3634 4.3315 0.6366 1.3439 77 (XX 10 0.2298 .2278 .3575 .9737 .9884 2339 .3691 4.2747 .6309 1.3410 50 20 0.2327 .2306 .3629 .9730 .9881 2370 .3748 4.2193 .6252 1.3381 40 30 0.2356 .2334 .3682 .9724 .9878 2401 .3804 4.1653 .6196 1.3352 30 40 0.2385 .2363 .3734 .9717 .9875 2432 .3859 4.1126 .6141 1.3323 20 50 0.2414 .2391 .3786 .9710 .9872 2462 .3914 4.0611 .6086 1.3294 10 14 00' 0.2443 .2419 9.3837 .9703 9.9869 2493 9.3968 4.0108 0.6032 1.3265 76 (XX 10 0.2473 .2447 .3887 .9696 .9866 2524 .4021 3.9617 .5979 1.3235 50 20 0.2502 .2476 .3937 .9689 .9863 2555 .4074 3.9136 .5926 1.3206 40 30 0.2531 2504 .3986 .9681 .9859 2586 .4127 3.8667 .5873 1.3177 30 40 0.2560 2532 .4035 .9674 .9856 2617 .4178 3.8208 .5822 1.3148 20 50 0.2589 2560 .4083 .9667 .9853 2648 .4230 3.7760 .5770 13119 10 15 00' 0.2618 .2588 9.4130 .9659 9.9849 2679 9.4281 3.7321 0.5719 1.3090 75 00' 10 0.2647 2616 .4177 .9652 .9846 2711 .4331 3.6891 .5669 1.3061 50 20 0.2676 2644 .4223 .9644 .9843 .2742 .4381 3.6470 .5619 1.3032 40 30 0.2705 2672 .4269 .9636 -.9839 .2773 .4430 3.6059 .5570 1.3003 30 40 0.2734 2700 .4314 .9628 .9836 2805 .4479 3.5656 .5521 1.2974 20 50 0.2763 2728 .4359 .9621 .9832 2836 -4527 3.5261 .5473 U945 10 16 00' 0.2793 2756 9.4403 .9613 9.9828 .2867 9.4575 3.4874 0.5425 12915 74 (XX 10 0.2822 2784 .4447 .9605 .9825 2899 .4622 3.4495 .5378 12886 50 20 0.2851 2812 .4491 ^9596 .9821 2931 .4669 3.4124 .5331 1.2857 40 30 0.2880 2840 .4533 .9588 .9817 2962 .4716 3.3759 .5284 1.2828 30 40 0.2909 2868 .4576 .9580 .9814 2994 .4762 3.3402 .5238 12799 20 50 0.2938 2896 .4618 .9572 .9810 .3026 .4808 3.3052 .5192 12770 10 17 (XX 0.2967 2924 9.4659 .9563 9.9806 .3057 9.4853 3.2709 0.5147 1.2741 3 (XX 10 0.2996 2952 .4700 .9555 .9802 3089 .4898 3.2371 .5102 12712 50 20 0.3025 2979 .4741 .9546 .9798 3121 .4943 3.2041 .5057 1.2683 40 30 0.3054 3007 .4781 9537 .9794 3153 .4987 3.1716 .5013 1.2654 30 40 0.3083 3035 .4821 9528 .9790 3185 .5031 3.1397 .4969 1.2625 20 50 0.3113 3062 .4861 9520 .9786 3217 .5075 3.1084 .4925 12595 10 18 (XX 0.3142 3090 9.4900 9511 9.9782 3249 9.5118 3.0777 0.4882 12566 2 (XX Nat. Log.* Nat. Log.* Nat. Log.* Nat. Log. Cosines Sines Cotangents Tangents Ra- dians De- grees 54 MATHEMATICAL TABLES TRIGONOMETRIC FUNCTIONS Annex 10 in columns marked*. (continued) (For O.l intervals, Bee pp. 46-51) De- grees Ra- dians Sines Cosines Tangents Cotangents Nat. Log. * Nat. Log.* Nat. Log.* Nat. Log. 18 00' 0.3142 .3090 9.4900 .9511 9.9782 .3249 9.5118 3.0777 0.4882 1.2566 72 00* 10 0.3171 .3118 .4939 .9502 .9778 .3281 .5161 3.0475 .4839 1.2537 50 20 0.3200 .3145 .4977 .9492 .9774 .3314 .5203 3.0178 .4797 1.^508 40 30 0.3229 .3173 .5015 .9483 .9770 ,3346 .5245 2.9887 .4755 1.2479 30 40 0.3258 .3201 .5052 .9474 .9765 .3378 .5287 2.9600 .4713 1 .2450 20 50 0.3287 .3228 .5090 .9465 .9761 .3411 .5329 2.9319 .4671 1.2421 10 19 00' 0.3316 .3256 9.5126 .9455 9.9757 .3443 9.5370 2.9042 0.4630 1.2392 71 00' 10 0.3345 .3283 .5163 .9446 .9752 .3476 3411 2.8770 .4589 1.2363 50 20 0.3374 .3311 .5199 .9436 .9748 .3508 .5451 2.8502 .4549 1 .2334 40 30 0.3403 .3338 .5235 .9426 .9743 .3541 .5491 2.8239 .4509 1.2305 30 40 0.3432 .3365 .5270 .9417 .9739 .3574 .5531 2.7980 .4469 .2275 20 50 0.3462 .3393 .5306 .9407 .9734 .3607 .5571 2.7725 .4429 12246 10 20 00' 0.3491 .3420 9.5341 .9397 9.9730 .3640 9.5611 2.7475 0.4389 1.2217 70 00' 10 0.3520 .3448 .5375 .9387 .9725 .3673 .5650 2.7228 .4350 1.2188 50 20 0.3549 3475 .5409 .9377 .9721 .3706 .5689 2.6985 .4311 1.2159 40 30 0.3578 .3502 .5443 .9367 .9716 .3739 .5727 2.6746 .4273 1.2130 30 40 0.3607 .3529 .5477 .9356 .971 1 .3772 .5766 2.6511 .4234 1.2101 20 50 0.3636 .3557 .5510 .9346 .9706 .3805 .5804 2.6279 .4196 1.2072 10 21 00' 0.3665 .3584 9.5543 .9336 9.9702 .3839 9.5842 2.6051 0.4158 1.2043 69 0(X 10 0.3694 .361 1 .5576 .9325 .9697 .3872 .5879 2.5826 .4121 1.2014 50 20 0.3723 .3638 .5609 .9315 .9692 .3906 .5917 2.5605 .4083 .1985 40 30 0.3752 .3665 .5641 .9304 .9687 .3939 .5954 2.5386 .4046 .1956 30 40 0.3782 .3692 .5673 .9293 .9682 .3973 .5991 2.5172 .4009 .1926 20 50 0.381 1 .3719 .5704 .9283 .9677 .4006 .6028 2.4960 .3972 .1897 10 22 00' 0.3840 .3746 9.5736 .9272 9.9672 .4040 9.6064 2.4751 0.3936 .1868 68 00' 10 0.3869 .3773 .5767 .9261 .9667 .4074 .6100 2.4545 .3900 .1839 50 20 0.3898 .3800 .5798 .9250 .9661 .4108 .6136 2.4342 .3864 .1810 40 30 0.3927 .3827 .5828 .9239 .9656 .4142 .6172 2.4142 .3828 .1781 30 40 0.3956 .3854 .5859 .9228 .9651 .4176 .6208 2.3945 .3792 .1752 20 50 0.3985 .3881 .5889 .9216 .9646 .4210 .6243 2.3750 .3757 .1723 10 23 00' 0.4014 .3907 9.5919 .9205 9.9640 .4245 9.6279 2.3559 0.3721 .1694 67 00' 10 0.4043 .3934 .5948 .9194 .9635 .4279 .6314 2.3369 .3686 .1665 50 20 0.4072 .3961 .5978 .9182 .9629 .4314 .6348 2.3183 .3652 .1636 40 30 0.4102 .3987 .6007 .9171 .9624 .4348 .6383 2.2998 .3617 .1606 30 30 0.4131 .4014 .6036 .9159 .9618 .4383 .6417 2.2817 .3583 .1577 20 50 0.4160 .4041 .6065 .9147 .9613 .4417 .6452 2.2637 .3548 .1548 10 24 00' 0.4189 .4067 9.6093 .9135 9.9607 .4452 9.6486 2.2460 0.3514 .1519 66 00' 10 0.4218 .4094 .6121 .9124 .9602 .4487 .6520 2.2286 .3480 .1490 50 20 0.4247 .4120 .6149 .9112 .9596 .4522 .6553 2.2113 .3447 .1461 40 30 0.4276 .4147 .6177 .9100 .9590 .4557 .6587 2.1943 .3413 .1432 30 40 0.4305 .4173 .6205 .9088 .9584 .4592 .6620 2.1775 .3380 .1403 20 50 0.4334 .4100 .6232 .9075 .9579 .4628 .6654 2.1609 .3346 .1374 10 25 0(K 0.4363 .4226 9.6259 .9063 9.9573 .4663 9.6687 2.1445 0.3313 .1345 65 00' 10 0.4392 .4253 .6286 .9051 .9567 .4699 .6720 2.1283 .3280 .1316 50 20 0.4422 .4279 .6313 .9038 .9561 .4734 .6752 2.1123 .3248 .1286 40 30 0.4451 .4305 .6340 .9026 .9555 .4770 .6785 2.0965 .3215 .1257 30 40 0.4480 .4331 .6366 .9013 .9549 .4806 .6817 2.0809 .3183 .1228 20 50 0.4509 .4358 .6392 .9001 .9543 .4841 .6850 2.0655 .3150 .1199 10 26 00' 0.4538 .4384 9.6418 .8988 9.9537 .4877 9.6882 2.0503 0-3118 .1170 64 00' 10 0.4567 .4410 .6444 .8975 .9530 .4913 .6914 2.0353 .3086 .1141 50 20 0.4596 .4436 .6470 .8962 .9524 .4950 .6946 2.0204 .3054 .1112 40 30 0.4625 .4462 .6495 .8949 .9518 .4986 .6977 2.0057 .3023 .1083 30 40 0.4654 .4488 .6521 .8936 .9512 .5022 .7009 1.9912 .2991 .1054 20 50 0.4683 .4514 .6546 .8923 .9505 .5059 .7040 1.9768 .2960 .1025 10 27 (XX 0.4712 .4540 9.6570 .8910 9.9499 .5095 9.7072 1.9626 0.2928 1.0996 63 00' Nat. Log.* Nat. Log.* Nat. Log.* Nat. Log. Cosines Sines Cotangents Tangents Ra- dians De- grees MATHEMATICAL TABLES 55 TRIGONOMETRIC FUNCTIONS (continued) Annex -10 in columns marked*. (For 0.l intervals, see pp. 46-51) De- grees Ra- dians Sines Cosines Tangents Cotangents Nat. Log.* Nat. Log.* Nat. Log.* Nat. Log. 27 00' 0.4712 .4540 9.6570 .8910 9.9499 .5095 9.7072 1.9626 0.2928 1.0996 63 00' 10 0.4741 .4566 .6595 .8897 .9492 .5132 .7103 1.9486 2897 1.0966 50 20 0.4771 .4592 .6620 .8884 .9486 .5169 .7134 1.9347 .2866 1.0937 40 30 0.4800 .4617 .6644 .8870 .9479 .5206 .7165 1.9210 .2835 1.0908 30 40 0.4829 .4643 .6668 .8857 .9473 .5243 .7196 1.9074 .2804 1.0879 20 50 0.4858 .4669 .6692 .8843 .9466 .5280 .7226 1.8940 .2774 1.0850 10 28 00' 0.4887 .4695 9.6716 .8829 9.9459 .5317 9.7257 1.8807 0.2743 1.0821 62 00' 10 0.4916 .4720 .6740 .8816 .9453 .5354 .7287 1.8676 .2713 1.0792 50 20 0.4945 .4746 .6763 .8802 .9446 .5392 .7317 1.8546 .2683 1.0763 40 30 0.4974 .4772 .6787 .8788 .9439 .5430 .7348 1.8418 .2652 1.0734 30 40 0.5003 .4797 .6810 .8774 .9432 .5467 .7378 1.8291 .2622 1.0705 20 50 0.5032 .4823 .6833 .8760 .9425 .5505 .7408 1.8165 .2592 1.0676 10 29 00' 0.5061 .4848 9.6856 .8746 9.9418 .5543 9.7438 1.8040 0.2562 1.0647 61 00' 10 0.5091 .4874 .6878 .8732 .941 1 .5581 .7467 1.7917 .2533 1.0617 50 20 0.5120 .4899 .690! .8718 .9404 .5619 .7497 1.7796 .2503 1.0588 40 30 0.5149 .4924 .6923 .8704 .9397 .5658 .7526 1.7675 .2474 1.0559 30 40 0.5178 .4950 .6946 .8689 .9390 .5696 .7556 1.7556 .2444 1.0530 20 50 0.5207 .4975 .6968 .8675 .9383 .5735 .7585 1.7437 .2415 1.0501 10 30 00' 0.5236 .5000 9.6990 .8660 9.9375 .5774 9.7614 1.7321 0.2386 1.0472 60 00' 10 0.5265 .5025 .7012 .8646 .9368 .5812 .7644 1.7205 .2356 1.0443 50 20 0.5294 .5050 .7033 .8631 .9361 .5851 .7673 1.7090 .2327 1.0414 40 30 0.5323 .5075 .7055 .8616 .9353 .5890 .7701 1.6977 .2299 1.0385 30 40 0.5352 .5100 .7076 .8601 .9346 .5930 .7730 1.6864 .2270 1.0356 20 50 0.5381 .5125 .7097 .8587 .9338 .5969 .7759 1.6753 .2241 1.0327 10 31 00' 0.5411 .5150 9.7118 .8572 9.9331 .6009 9.7788 1.6643 0.2212 1.0297 59 00' 10 0.5440 .5175 .7139 .8557 .9323 .6048 .7816 1.6534 .2184 1.0268 50 20 0.5469 .5200 .7160 .8542 .9315 .6088 .7845 1.6426 .2155 1.0239 40 30 0.5498 .5225 .7181 .8526 .9308 .6128 .7873 1.6319 .2127 1.0210 30 40 0.5527 .5250 .7201 .8511 .9300 .6168 .7902 1.6212 .2098 1.0181 20 50 0.5556 .5275 .7222 .8496 .9292 .6208 .7930 1.6107 .2070 1.0152 10 32 00' 0.5585 .5299 9.7242 .8480 9.9284 .6249 9.7958 .6003 0.2042 1.0123 58 00' 10 0.5614 .5324 .7262 .8465 .9276 .6289 .7986 .5900 .2014 1.0094 50 20 0.5643 .5348 .7282 .8450 .9268 .6330 .8014 .5798 .1986 1 .0065 40 30 0.5672 .5373 .7302 .8434 .9260 .6371 .8042 .5697 .1958 1.0036 30 40 0.5701 .5398 .7322 .8418 .9252 .6412 .8070 .5597 .1930 1.0007 20 50 0.5730 5422 .7342 .8403 .9244 .6453 .8097 .5497 .1903 0.9977 10 33 (XX 0.5760 5446 9.7361 .8387 9.9236 .6494 9.8125 .5399 0.1875 0.9948 57 00' 10 0.5789 5471 .7380 .8371 .9228 .6536 .8153 .5301 .1847 0.9919 50 20 0.5818 5495 .7400 .8355 .9219 .6577 .8180 .5204 .1820 0.9890 40 30 0.5847 5519 .7419 .8339 .9211 .6619 .8208 .5108 .1792 0.9861 30 40 0.5876 5544 .7438 .8323 .9203 .6661 .8235 .5013 .1765 0.9832 20 50 0.5905 5568 .7457 .8307 .9194 .6703 .8263 .4919 .1737 0.9803 10 34 00' 0.5934 5592 9.7476 .8290 9.9186 .6745 9.8290 .4826 0.1710 09774 56 00' 10 0.5963 5616 .7494 .8274 .9177 .6787 .8317 .4733 .1683 0.9745 50 20 0.5992 5640 .7513 .8258 .9169 .6830 .8344 .4641 .1656 0.9716 40 30 0.6021 5664 .7531 .8241 .9160 .6873 .8371 .4550 .1629 0.9687 30 40 0.6050 5688 .7550 .8225 .9151 .6916 .8398 .4460 .1602 0.9657 20 50 0.6080 5712 .7568 .8208 .9142 .6959 .8425 .4370 .1575 0.9628 10 35 00' 0.6109 5736 9.7586 .8192 9.9134 .7002 9.8452 .4281 0.1548 0.9599 55 00' 10 0.6138 5760 .7604 .8175 .9125 .7046 .8479 .4193 .1521 0.9570 50 20 0.6167 5783 .7622 .8158 .9116 .7089 .8506 .4106 .1494 0.9541 40 30 0.6196 5807 .7640 .8141 .9107 .7133 .8533 .4019 .1467 0.9512 30 40 0.6225 5831 .7657 .8124 .9098 .7177 .8559 .3934 .1441 0.9483 20 50 0.6254 5854 .7675 .8107 .9089 .7221 .8586 .3848 .1414 0.9454 10 36 00' 0.6283 5878 9.7692 .8090 9.9080 .7265 9.8613 1.3764 0.1387 0.9425 54 00' Nat. Log.* Nat. Log.* Nat. Log.* Nat. Log. Cosines Sines Cotangents Tangents Ra- dians De- grees 56 MATHEMATICAL TABLES TRIGONOMETRIC FUNCTIONS (continued) Annex -10 in columns marked*. (For 0.l intervals, see pp. 4.6-51) De- grees Ra- dians Sines Cosines Tangents Cotangents Nat. Log.* Nat. Log.* Nat. Log.* Nat. Log. 36 (XX 0.6283 3878 9.7692 .8090 9.9080 .7265 9.8613 1.3764 0.1387 0.9425 54 00' 10 0.6312 .5901 .7710 .8073 .9070 .7310 .8639 1.3680 .1361 0.9396 50 20 0.6341 .5925 .7727 .8056 .9061 .7355 .8666 1.3597 .1334 0.9367 40 ' 30 0.6370 .5948 .7744 .8039 .9052 .7400 .8692 1.3514 .1308 0.9338 30 40 0.6400 .5972 .7761 .8021 .9042 .7445 .8718 1.3432 .1282 0.9308 20 50 0.6429 .5995 .7778 .8004 .9033 .7490 .8745 1.3351 .1255 0.9279 10 37 00' 0.6458 .6018 9.7795 .7986 9.9023 .7536 9.8771 .3270 0.1229 0.9250 53 00' 10 0.6487 .6041 .781 1 .7969 .9014 .7581 .8797 .3190 .1203 0.9221 50 20 0.6516 .6065 .7828 .7951 .9004 .7627 .8824 .3111 .1176 0.9192 40 30 0.6545 .6088 .7844 .7934 .8995 .7673 .8850 .3032 .1150 0.9163 30 40 0.6574 .61 1 1 .7861 .7916 .8985 .7720 .8876 .2954 .1124 0.9134 20 50 0.6603 .6134 .7877 .7898 .8975 .7766 .8902 .2876 .1098 0.9105 10 38 00' 0.6632 .6157 9.7893 .7880 9.8965 .7813 9.8928 .2799 0.1072 0.9076 52 00' 10 0.6661 .6180 .7910 .7862 .8955 .7860 .8954 .2723 .1046 0.9047 50 20 0.6690 .6202 .7926 .7844 .8945 .7907 .8980 .2647 .1020 0.9018 40 30 0.6720 .6225 .7941 .7826 .8935 .7954 .9006 .2572 .0994 0.8988 30 40 0.6749 .6248 .7957 .7808 .8925 .8002 .9032 .2497 .0968 0.8959 20 50 0.6778 .6271 .7973 .7790 .8915 .8050 .9058 .2423 .0942 0.8930 10 39 00' 0.6807 .6293 9.7989 .7771 9.8905 .8098 9.9084 .2349 0.0916 0.8901 51 00' 10 0.6836 .6316 .8004 .7753 .8895 .8146 .9110 .2276 .0890 0.8872 50 20 0.6865 .6338 .8020 .7735 .8884 .8195 .9135 .2203 .0865 0.8843 40 30 0.6894 .6361 .8035 .7716 .8874 .8243 .9161 .2131 .0839 0.8814 30 40 0.6923 .6383 .8050 .7698 .8864 .8292 .9187 .2059 .0813 0.8785 20 50 0.6952 .6406 .8066 .7679 .8853 .8342 .9212 .1988 .0788 0.8756 10 40 00' 0.6981 .6428 9.8081 .7660 9.8843 .8391 9.9238 .1918 0.0762 0.8727 50 00' 10 0.7010 .6450 .8096 .7642 .8832 .8441 .9264 .1847 .0736 0.8698 50 20 0.7039 .6472 .81 1 1 .7623 .8821 .8491 .9289 .1778 .0711 0.8668 40 30 0.7069 .6494 .8125 .7604 .8810 .8541 .9315 .1708 .0685 0.8639 30 40 0.7098 .6517 .8140 .7585 .8800 .8591 .9341 .1640 .0659 0.8610 20 50 0.7127 .6539 .8155 .7566 .8789 .8642 .9366 .1571 .0634 0.8581 10 41 00' 0.7156 .6561 9.8169 .7547 9.8778 .8693 9.9392 .1504 0.0608 0.8552 49 00' 10 0.7185 .6583 .8184 .7528 .8767 .8744 .9417 J436 .0583 0.8523 50 20 0.7214 .6604 .8198 .7509 .8756 .8796 .9443 .1369 .0557 0.8494 40 30 0.7243 .6626 .8213 .7490 .8745 .8847 .9468 .1303 .0532 0.8465 30 40 0.7272 .6648 .8227 .7470 .8733 .8899 .9494 .1237 .0506 0.8436 20 50 0.7301 .6670 .8241 .7451 .8722 .8952 .9519 .1171 .0481 0.8407 10 42 00' 0.7330 .6691 9.8255 .7431 9.8711 .9004 9.9544 .1106 00456 0.8378 48 00' 10 0.7359 .6713 .8269 .7412 .8699 .9057 .9570 .1041 .0430 0.8348 50 20 0.7389 .6734 .8283 .7392 .8688 .9110 .9595 1 .0977 .0405 0.8319 40 30 0.7418 .6756 .8297 .7373 .8676 .9163 .9621 1.0913 .0379 0.8290 30 40 0.7447 .6777 .8311 .7353 .8665 .9217 .9646 1.0850 .0354 0.8261 20 50 0.7476 .6799 .8324 .7333 .8653 .9271 .9671 1.0786 .0329 0.8232 10 43 00' 0.7505 .6820 9.8338 .7314 9.8641 .9325 9.9697 1.0724 0.0303 0.8203 47 00' 10 0.7534 .6841 .8351 .7294 .8629 .9380 .9722 1.0661 .0278 0.8174 50 20 0.7563 .6862 .8365 .7274 .8618 .9435 .9747 1.0599 .0253 0.8145 40 30 0.7592 .6884 .8378 .7254 .8606 .9490 .9772 1.0538 .0228 0.8116 30 40 0.7621 .6905 .8391 .7234 .8594 .9545 .9798 1.0477 .0202 0.8087 20 50 0.7650 .6926 .8405 .7214 .8582 .9601 .9823 1.0416 .0177 0.8058 10 44 00' 0.7679 .6947 9.8418 .7193 9.8569 .9657 9.9848 1.0355 0.0152 0.8029 46 00' 10 0.7709 .6967 .8431 .7173 .8557 .9713 .9874 1.0295 .0126 0.7999 50 20 0.7738 .6988 .8444 .7153 .8545 .9770 .9899 1.0235 .0101 0.7970 40 30 0.7767 .7009 .8457 .7133 .8532 .9827 .9924 1.0176 .0076 0.7941 30 40 07796 .7030 .8469 .7112 .8520 .9884 .9949 1.0117 .0051 0.7912 20 50 0.7825 .7050 .8482 .7092 .8507 .9942 .9975 1.0058 .0025 0.7883 10 45 00' 0.7854 .7071 9.8495 .7071 9.8495 1.0000 0.0000 1.0000 0.0000 0.7854 45 00' Nat. Log.* Nat. Log.* Nat. Log.* Nat. Log. Cosines Sines Cotangents Tangents Ra- dians De- grees MATHEMATICAL TABLES EXPONENTIALS [e and logioe (see p. 62). For graph*, see p. 174. MATHEMATICAL TABLES 59 HYPERBOLIC LOGARITHMS (continued} e^ 3 5, sinh x = W(e*) and logio sinh x = (0.4343)z + 0.6990 1, correct to four significant figures. For table of multiples of 0.4343, see p. 62. Graphs, p. 174. MATHEMATICAL TABLES 61 HYPERBOLIC COSINES [cosh x = K(e* +e~*)] V 1 2 3 4 5 6 7 8 9 0.0 1.000 1.000 1.000 1.000 1.001 1.001 1.002 1.002 1.003 1.004 1 1 .005 1.006 1.007 1.008 1.010 1.011 1.013 1.014 1.016 1.018 2 2 .020 1.022 1.024 1.027 1.029 1.031 1.034 1.037 1.039 1.042 3 3 .045 1.048 .052 1.055 1.058 1.062 1.066 1.069 1.073 1.077 4 4 .081 1.085 .090 1.094 1.098 1.103 1.108 1.112 1.117 1.122 5 0.5 .128 1.133 .138 1.144 1.149 1.155 1.161 1.167 1.173 1.179 6 6 .185 1.192 .198 1.205 1.212 1.219 1.226 1.233 1.240 1.248 7 7 .255 1.263 .271 1.278 1.287 1.295 1.303 1.311 1.320 1.329 8 8 .337 1.346 .355 1.365 1.374 1.384 1.393 1.403 1.413 1.423 10 9 1.433 1.443 .454 1.465 1.475 1.486 1.497 1.509 1.520 1.531 11 1.0 1.543 1.555 1.567 1.579 1.591 1.604 1.616 1.629 1.642 1.655 13 1 1.669 1.682 1.696 1.709 1.723 1.737 1.752 1.766 1.781 1.796 14 2 1.811 1.826 1.841 1.857 1.872 1.888 1.905 1.921 1.937 1.954 16 3 1.971 1.988 2.005 2.023 2.040 2.058 2.076 2.095 2.113 2.132 18 4 2.151 2.170 2.189 2.209 2.229 2.249 2.269 2.290 2.310 2.331 20 1.5 2.352 2.374 2.395 2.417 2.439 2.462 2.484 2.507 2.530 2.554 23 6 2.577 2.601 2.625 2.650 2.675 2.700 2.725 2.750 2.776 2.802 25 7 2.828 2.855 2.882 2.909 2.936 2.964 2.992 3.021 3.049 3.078 28 8 3.107 3.137 3167 3.197 3.228 3.259 3.290 3.321 3.353 3.385 31 9 3.418 3.451 3.484 3.517 3.551 3.585 3.620 3.655 3.690 3.726 34 2.0 3.762 3.799 3.835 3.873 3.910 3.948 3.987 4.026 4.065 4.104 38 1 4.144 4.185 4.226 4.267 4.309 4.351 4.393 4.436 4.480 4.524 42 2 4.568 4.613 4.658 4.704 4.750 4.797 4.844 4.891 4.939 4.988 47 3 5.037 5.087 5.137 5.188 5.239 5.290 5.343 5.395 5.449 5.503 52 4 5.557 5.612 5.667 5.723 5.780 5.837 5.895 5.954 6.013 6.072 58 2.5 6.132 6.193 6.255 6.317 6.379 6.443 6.507 6.571 6.636 6.702 64 6 6.769 6.836 6.904 6.973 7.042 7.112 7.183 7.255 7.327 7.400 70 7 7.473 7.548 7.623 7.699 7.776 7.853 7.932 8.011 8.091 8.171 78 8 8.253 8.335 8.418 8.502 8.587 8.673 8.759 8.847 8.935 9.024 86 9 9.115 9.206 9.298 9.391 9.484 9.579 9.675 9.772 9.869 9.968 95 3.0 10.07 10.17 10.27 10.37 10.48 10.58 10.69 10.79 10.90 11.01 11 1 11.12 11.23 11.35 11.46 11.57 11.69 11.81 11.92 12.04 12.16 12 2 12.29 12.41 12.53 12.66 12.79 12.91 13.04 13.17 13.31 13.44 13 3 13.57 13.71 13.85 13.99 14.13 14.27 14.41 14.56 14.70 14.85 14 4 15.00 15.15 15.30 15.45 15.ftl 15.77 15.92 16.08 16.25 16.41 16 3.5 16.57 16.74 16.91 17.08 17.25 17.42 17.60 17.77 17.95 18.13 17 6 18.31 18.50 18.68 18.87 19.06 19.25 19.44 19.64 19.84 20.03 19 7 8 20.24 22.36 20.44 22.59 20.64 22.81 20.85 23.04 21.06 23.27 21.27 23.51 21.49 23.74 21.70 23.98 21.92 24.22 22.14 24.47 21 23 9 24.71 24.96 25.21 25.46 25.72 25.98 26.24 26.50 26.77 27.04 26 4.0 27.31 27.58 27.86 28.14 28.42 28.71 29.00 29.29 29.58 29.88 29 1 30.18 30.48 30.79 31.10 31.41 31.72 32.04 32.37 32.69 33.02 32 2 33.35 33.69 34.02 34.37 34.71 35.06 35.41 35.77 36.13 36.49 35 3 36.86 37.23 37.60 37.98 38.36 38.75 39.13 39.53 39.93 40.33 39 4 40.73 41.14 41.55 41.97 42.39 42.82 43.25 43.68 44.12 44.57 43 4.E 45.01 45.47 45.92 46.38 46.85 47.32 47.80 48.28 48.76 49.25 47 6 49.75 50.25 50.75 51.26 51.78 52.30 52.82 53.35 53.89 54.43 52 7 54.98 55.53 56.09 56.65 57.22 57.80 58.38 58.96 59.56 60.15 58 8 60.76 61.37 61.99 62.61 63.24 63.87 64.52 65.16 65.82 66.48 64 9 67.15 67.82 68.50 69.19 69.89 70.59 71.30 72.02 72.74 73.47 71 5.0 74.21 If x > 5, cosh x = ^i(e*) and logio cosh x = (0.4343)* + 0.6990 1, correct to four signifi- cant figures. For table of multiples of 0.4343, see p. 62. Graphs, p. 174. 62 MATHEMATICAL TABLES HYPEEBOLIC TANGENTS [tanh x = (e*-e~*) /(e* + 5, tanh a; = 1.0000 to four decimal places. Graphs, p . 174. MULTIPLES OF 0.4343 (0.43429448 = logw e) X 1 2 3 4 5 6 7 8 9 0. 0.0000 0.0434 0.0869 0.1303 0.1737 0.2171 0.2606 0.3040 0.3474 0.390< 1. 0.4343 0.4777 0.5212 0.5646 0.6080 0.6514 0.6949 0.7383 0.7817 0.825: 2. 0.8686 0.9120 0.9554 0.9989 1.0423 1.0857 1.1292 1.1726 1.2160 1 .259! 3. 1 .3029 1.3463 1.3897 1.4332 1.4766 1.5200 1.5635 1.6069 1.6503 1 .6933 4. 1.7372 1.7806 1.8240 1.8675 1.9109 1.9543 1.9978 2.0412 2.0846 2.128( 5. 2.1715 2.2149 2.2583 2.3018 2.3452 2.3886 2.4320 2.4755 2.5189 2.5622 6. 2.6058 2.6492 2.6926 2.7361 2.7795 2.8229 2.8663 2.9098 2.9532 2.996* 7. 3.0401 3.0835 3.1269 3.1703 3.2138 3.2572 3.3006 3.3441 3.3875 3.43TC 8. 3.4744 3.5178 3.5612 3.6046 3.6481 3.6915 3.7349 3.7784 3.8218 3.8652 9. 3.9087 3.9521 3.9955 4.0389 4.0824 4.1258 4.1692 4.2127 4.2561 4.299* MULTIPLES OP 2.3026 (2.3025851 = 1/0.4343) x 1 2 3 4 5 6 7 8 9 0. 0.0000 0.2303 0.4605 0.6908 0.9210 1.1513 1.3816 1.6118 1.8421 2.0723 1. 2.3026 2.5328 2.7631 2.9934 3.2236 3.4539 3.6841 3.9144 4.1447 4.3749 2. 4.6052 4.8354 5.0657 5.2959 5.5262 5.7565 5.9867 6.2170 6.4472 6.6775 3. 6.9078 7.1380 7.3683 7.5985 7.8288 8.0590 8.2893 8.5196 8.7498 8.9801 4. 9.2103 9.4406 9.6709 9.901 1 10.131 10.362 10.592 10.822 11.052 11.283 5. 11.513 11.743 11.973 12.204 12.434 12.664 12.894 13.125 13.355 13.585 6. 13.816 14.046 14.276 14.506 14.737 14.967 15.197 15.427 15.658 15.888 7. 16.118 ' 16.348 16.579 16.809 17.039 17.269 17.500 17.730 17.960 18.190 8. 18.421 18.651 18.881 19.111 19.342 19.572 19.802 20.032 20.263 20.493 9. 20.723 20.954 21.184 21.414 21.644 21.875 22.105 22.335 22.565 22.796 MATHEMATICAL TABLES 63 STANDARD DISTRIBUTION OF RESIDUALS (p. 121) a = any positive quantity; y = the number of residuals which are numerically < a; r = the probable error of a single observation; n = number of observations. a y Diff. r n 0.0 .000 1 2 .054 .107 54 53 CO 3 4 .160 .213 JJ 53 51 0.5 6 7 .264 .314 .363 50 49 8 9 .411 .456 45 44 1.0 .500 1 .542 ^/ 2 3 .582 .619 40 37 4 .655 33 1.5 6 7 8 9 .688 .719 .748 .775 . .800 31 29 27 25 23 2.0 1 .823 .843 20 i (i 2 .862 1 7 3 4 .879 .895 17 16 13 2.5 .908 6 .921 7 8 .931 .941 10 10 9 .950 9 7 3.0 .957 1 .963 6 2 .969 6 3 .974 5 4 .978 4 4 3.5 .982 6 .985 3 7 .987 8 .990 3 9 .991 2 4.0 .993 6 5.0 .999 FACTORS FOR COMPUTING PROBABLE ERROR (p. 121) n Bessel Peters 0.6745 0.6745 0.8453 0.8453 V(n - 1) Vn(n-l) Vn(/i-l) n\/n 1 2 .6745 .4769 .5978 .4227 3 .4769 .2754 .3451 .1993 4 .3894 .1947 .2440 .1220 5 .3372 .1508 .1890 .0845 6 .3016 .1231 .1543 .0630 7 .2754 .1041 .1304 .0493 8 .2549 .0901 .1130 .0399 9 .2385 .0795 .0996 .0332 10 .2248 .0711 .0891 .0282 11 .2133 .0643 .0806 .0243 12 .2034 .0587 .0736 .0212 13 .1947 .0540 .0677 .0188 14 .1871 .0500 .0627 .0167 15 .1803 .0465 .0583 .0151 16 .1742 .0435 .0546 .0136 17 .1686 .0409 .0513 .0124 18 .1636 .0386 .0483 .0114 19 .1590 .0365 .0457 .0105 20 .1547 .0346 .0434 .0097 21 .1508 .0329 .0412 .0090 22 .1472 .0314 .0393 .0084 23 .1438 .0300 .0376 .0078 24 .1406 .0287 .0360 .0073 25 .1377 .0275 .0345 .0069 26 .1349 .0265 .0332 .0065 27 .1323 .0255 .0319 .0061 28 .1298 .0245 .0307 .0058 29 .1275 .0237 .0297 .0055 30 .1252 .0229 .0287 .0052 31 .1231 .0221 .0277 .0050 32 .1211 . .0214 .0268 .0047 33 .1192 .0208 .0260 .0045 34 .1174 .0201 .0252 .0043 35 .1157 .0196 .0245 .0041 36 .1140 .0190 .0238 .0040 37 .1124 .0185 .0232 .0038 38 .1109 .0180 .0225 .0037 39 .1094 .0175 .0220 .0035 40 .1080 .0171 .0214 .0034 45 .1017 .0152 .0190 .0028 50 .0964 .0136 .0171 .0024 55 .0918 .0124 .0155 .0021 60 .0878 .0113 .0142 .0018 65 .0843 .0105 .0131 .0016 70 .0812 .0097 .0122 .0015 75 .0784 .0091 .0113 .0013 80 .0759 .0085 .0106 .0012 85 .0736 .0080 .0100 .0011 90 .0715 .0075 .0094 .0010 95 .06% .0071 .0089 .0009 100 .0678 .0068 .0085 .0008 64 MATHEMATICAL TABLES COMPOUND INTEREST. AMOUNT OF A GIVEN PRINCIPAL The amount A at the end of n years of a given principal P placed at compouni interest to-day is A = P X x or A = P X y or A = P X z, according as the interes (at the rate of r per cent, per annum) is compounded annually, semi-annually, o quarterly; the factor x or y or z being taken from the following tables. Values of x. (Interest compounded annually; A = P X .) Years r = 2 2H 3 ?M 4 4$* 5 6 7 i 1.0200 1.0250 1.0300 1.0350 1.0400 1.0450 1.0500 1.0600 1.0700 2 1.0404 1.0506 1.0609 1.0712 1.0816 1.0920 1.1025 .1236 1.1449 3 1.0612 1.0769 1.0927 1.1087 1.1249 1.1412 1.1576 .1910 1.2250 4 1.0824 1. 1038 1.1255 1.1475 1.1699 1.1925 12155 .2625 1.3108 3 5 1.1041 1.1314 1.1593 1.1877 1.2167 1.2462 1.2763 .3382 1.4026 6 1.1262 1.1597 1.1941 1.2293 1.2653 1.3023 1.3401 .4185 1.5007 1 7 1.1487 1.1887 1.2299 1.2723 1.3159 1.3609 1.4071 .5036 1.6058 ** 8 1.1717 1.2184 1.2668 1.3168 1.3686 1.4221 1.4775 .5938 1.7182 Ja 9 1.1951 1.2489 1.3048 1.3629 1.4233 1.4861 1.5513 1.6895 1.8385 ^ ' 10 1.2190 1.2801 1.3439 1.4106 1.4802 1.5530 1.6289 1.7908 1.9672 if 11 1.2434 1.3121 1.3842 1.4600 1.5395 1.6239 1.7103 1.8983 2.1049 t, O 12 1.2682 1.3449 1.4258 1.5111 1.6010 1.6959 1.7959 2.0122 2.2522 ^"vT 13 1.2936 1.3785 1.4685 1.5640 1.6651 1.7722 1.8856 2.1329 2.4098 v*^ 14 13195 1.4130 1.5126 1.6187 1.7317 1.3519 1.9799 2.2609 2.5785 a~^~ 15 1.3459 1.4483 1.5580 1.6753 1.8009 19353 2.0789 2.3966 2.7590 S^i 16 1.3728 1.4845 1.6047 1.7340 1.8730 2.0224 2.1829 2.5404 2.9522 2 !l 17 1.4002 1.5216 1.6528 1.7947 1.9479 2.1134 2.2920 2.6928 3.1588 .5 H 18 1.4282 1.5597 1.7024 1.8575 2.0258 2.2085 2.4066 2.8543 3.3799 19 1.4568 1.5987 1.7535 1.9225 2.1068 2.3079 2.5270 3.0256 3.6165 20 1.4859 1.6386 1.8061 1.9898 2.1911 2.4117 2.6^533 3.2071 3.8697 -2 25 1.6406 1.8539 2.0938 2.3632 2.6658 3.0054 3.3864 4.2919 5.4274 .2 30 1.8114 2.0976 2.4273 2.8068 3.2434 3.7453 4.3219 5.7435 7.6123 g2 40 2.2080 2.6851 3.2620 3.9593 4.8010 5.8164 7.0400 10.286 14.974 50 2.6916 3.4371 4.3839 5.5849 7.1067 9.0326 1 1 .467 18.420 29.457 60 3.2810 4.3998 5.8916 7.8781 10.520 14.027 18.679 32.988 57.946 Values of y. (Interest compounded semi-annually; A = P X y.) Years r=2 2H 3 3H 4 4H 5 6 7 1 1.0201 1.0252 1.0302 1.0353 1.0404 1 .0455 1.0506 1.0609 1.0712 2 1.0406 1.0509 1.0614 1.0719 1.0824 1.0931 1.1038 1.1255 1.1475 3 1.0615 1.0774 1.0934 1.1097 1.1262 1.1428 1.1597 1.1941 1 .2293 4 1.0829 1.1045 1.1265 1.1489 1.1717 1.1948 1.2134 1.2668 1.3168 5 1.1046 1.1323 1.1605 1.1894 1.2190 1.2492 1.2801 1.3439 1.4106 6 1.1268 1.1608 1.1956 1.2314 1.2682 1.3060 1.3449 1.4258 1.5111 7 1.1495 1.1900 1.2318 1.2749 1.3195 1.3655 1.4130 1.5126 1 .61 87 5 8 1.1726 1.2199 1.2690 1.3199 1.3728 1.4276 1.4845 1.6047 1.7340 g^ 9 1.1961 1.2506 1.3073 1.3665 1.4282 1.4926 1.5597 1.7024 1.8575 g 10 1.2202 1.2820 1.3469 1.4148 1.4859 1.5605 1.6386 1.8061 1.9898 ~- 11 1.2447 1.3143 1.3876 1.4647 1.5460 1.6315 1.7216 1.9161 2.1315 v ~' 12 1.2697 1.3474 1.4295 1.5164 1.6084 1.7058 1.8087 2.0328 2.2833 + 13 1.2953 1.3812 1.4727 1.5700 1.6734 1.7834 1.9003 2.1566 2.4460 H 14 1.3213 1.4160 1.5172 1.6254 1.7410 1.8645 1.9965 2.2879 2.6202 II 15 1.3478 1.4516 1.5631 1.6828 1.8114 1.9494 2.0976 2.4273 2.8068 a 16 1.3749 1.4881 1.6103 1.7422 1.8845 2.0381 2.2038 2.5751 3.0067 17 1 .4026 1.5256 1.6590 1.8037 1.9607 2.1308 2.3153 2.7319 3.2209 jj 18 1.4308 1.5639 1.7091 1.8674 2.0399 2.2278 2.4325 2.8983 3.4503 "9 19 1.4595 1.6033 1.7608 1.9333 2.1223 2.3292 2.5557 3.0748 3.6960 S 20 1.4889 1.6436 1.8140 2.0016 2.2080 2.4352 2.6851 3.2620 3.9593 fe 25 1.6446 1.8610 2.1052 2.3808 2.6916 3.0420 3.4371 4.3839 5.5849 30 1.8167 2.1072 2.4432 2.8318 3.2810 3.8001 4.3998 5.8916 7.8781 40 2.2167 2.7015 3.2907 4.0064 4.8754 5.9301 7.2096 10.641 15.676 50 2.7048 3.4634 4.4320 5.6682 7.2446 9.2540 11.814 19.219 31.191 60 3.3004 4.4402 5.9693 8.0192 10.765 14.441 19.358 34.711 62.064 MATHEMATICAL TABLES 65 Values of z. (Interest compounded quarterly; A = P X 2; see opposite page) Years = 2 2H 3 3^ 4 4>i 5 6 7 1 .0202 .0252 1.0303 1.0355 1.0406 1.0458 1.0509 1.0614 1.0719 2 .0407 .0511 1.0616 1.0722 1.0829 1.0936 .1045 .1265 1.1489 3 .0617 .0776 1.0938 1.1102 1.1268 1.1437 .1608 .1956 1.2314 4 .0831 .1048 1.1270 1.1496 1.1726 1.1960 .2199 .2690 1.3199 5 .1049 .1327 1.1612 1.1903 1.2202 1.2508 .2820 .3469 1.4148 6 .1272 .1613 1.1964 1.2326 1.2697 1.3080 .3474 .4295 1.5164 _ 7 .1499 .1906 1.2327 1.2763 1.3213 1.3679 .4160 .5172 1.6254 X 8 .1730 .2206 1.2701 1.3215 1.3749 1.4305 .4881 1.6103 1.7422 o" 9 .1967 .2514 1.3086 1.3684 1.4308 1.4959 1.5639 1.7091 1.8674 3 10 .2208 .2830 1.3483 1.4169 1.4889 1.5644 1.6436 1.8140 2.0016 ^ 11 .2454 .3154 1.3893 1.4672 1.5493 1.6360 1.7274 1.9253 2.1454 12 .2705 .3486 1.4314 1.5192 1.6122 1.7108 1.8154 2.0435 2.2996 < 13 .2961 .3826 1.4748 1.5731 1.6777 1.7891 1.9078 2.1689 2.4648 ;-*. 14 .3222 .4175 1.5196 1.6288 1.7458 1.8710 2.0050 2.3020 2.6420 II 15 .3489 .4533 1.5657 1.6866 1.8167 1.9566 2.1072 2.4432 2.8318 M 16 .3760 .4900 1.6132 1.7464 1.8905 2.0462 2.2145 2.5931 3.0353 17 .4038 .5276 1.6621 1.8083 1.9672 2.1398 2.3274 2.7523 3.2534 J5 18 .4320 .5661 1.7126 1.8725 2.0471 2.2378 2.4459 2.9212 3.4872 19 .4609 .6056 ,1.7645 1.9389 2.1302 2.3402 2.5705 3.1004 3.7378 o 20 .4903 .6462 1.8180 2.0076 2.2167 2.4473 2.7015 3.2907 4.0064 A 25 .6467 .8646 2.1111 2.3898 2.7048 3.0609 3.4634 4.4320 5.6682 30 .8194 i .1121 2.4514 2.8446 3.3004 3.8285 4.4402 5.9693 8.0192 40 !.22ii ; '.7098 3.3053 4.0306 4.9138 5.9892 7.2980 10.828 16.051 50 5.7115 3 .4768 4.4567 5.7110 7.3160 9.3693 11.995 19.643 32.128 60 L3102 ^ L4608 6.0092 8.0919 10.893 14.657 19.715 35.633 64.307 AMOUNT OP AN ANNUITY The amount S accumulated at the end of n years by a given annual payment Y set aside at the end of each year is S =* F X , where the factor v is to be taken from the following table. (Interest at r per cent, per annum, compounded annually.) Values of v Years r= 2 2H 3 Hi 4 ^ 5 6 7 1 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1 .0000 2 2.0200 2.0250 2.0300 2.0350 2.0400 .2.0450 2.0500 2.0600 2.0700 3 3.0604 3.0756 3.0909 3.1062 3.1216 3.1370 3.1525 3.1836 3.2149 4 4.1216 4.1525 4.1836 4.2149 4.2465 4.2782 4.3101 4.3746 4.4399 O 5 5.2040 5.2563 5.3091 5.3625 5.4163 5.4707 5.5256 5.6371 5.7507 > 6 6.3081 6.3877 6.4684 6.5502 6.6330 6.7169 6.8019 6.9753 7.1533 .1. 7 7.4343 7.5474 7.6625 7.7794 7.8983 8.0192 8.1420 8.3938 8.6540 I 8 8.5830 8.7361 8.8923 9.0517 9.2142 9.3800 9.5491 9.8975 10.260 ^ 9 9.7546 9.9545 10.159 10.368 10.583 10.802 11.027 11.491 11.978 1 ; 10 10.950 11.203 11.464 11.731 12.006 12.288 12.578 13.181 13.816 S 11 12.169 12.483 12.808 13.142 13.486 13.841 14.207 14.972 15.784 11 o 12 13.412 13.796 14.192 14.602 15.026 15.464 15.917 16.870 17.888 !> 13 14.680 15.140 15.618 16.113 16.627 17.160 17.713 18.882 20.141 14 15.974 16.519 17.086 17.677 18.292 18.932 19.599 21.015 22.550 > ! 15 17.293 17.932 18.599 19.296 20.024 20.784 21.579 23.276 25.129 + 7 16 18.639 19.380 20.157 20.971 21.825 22.719 23.657 25.673 27.888 ^ 1 17 20.012 20.865 21.762 22.705 23.698 24.742 25.840 28.213 30.840 " vS 18 21.412 22.386 23.414 24.500 25.645 26.855 28.132 30.906 33.999 ^ 19 22.841 23.946 25.117 26.357 27.671 29.064 30.539 33.760 37.379 11 20 24.297 25.545 26.870 28.280 29.778 31.371 33.066 36.786 40.995 25 32.030 34.158 36.459 38.950 41.646 44.565 47.727 54.865 63.249 a 30 40.568 43.903 47.575 51.623 56.085 61.007 66.439 79.058 94.461 1 40 60.402 67.403 75.401 84.550 95.026 107.03 120.80 154.76 199.64 i 50 84.579 97.484 112.80 131.00 152.67 178.50 209.35 290.34 406.53 PH 60 114.05 135.99 163.05 196.52 237.99 289.50 353.58 533.13 813.52 66 MATHEMATICAL TABLES PRINCIPAL WHICH WILL AMOUNT TO A GIVEN SUM The principal P, which, if placed at compound interest to-day, will amount to a giv< sum A at the end of n years is P = A X x' or P = A X y' or P = A X z', according the interest (at the rate of r per cent, per annum) is compounded annually, semi-annuall or quarterly: the factor x' or y' or z' being taken from the following tables. Values of x'. (Interest compounded annually; P = A X x') Years r = 2 2H 3 sw 4 4H 5 6 7 1 .98039 .97561 .97087 .96618 .96154 .95694 .95238 .94340 .93458 2 .96117 .95181 .94260 .93351 .92456 .91573 .90703 .89000 .87344 3 .94232 .92860 .91514 .90194 .88900 .87630 .86384 .83962 .81630 4 .92385 .90595 .88849 .87144 .85480 .83856 .82270 .79209 .76290 . 5 .90573 C 88385 .86261 .84197 .82193 .80245 .78353 .74726 .71299 i-H 6 .88797 .86230 .83748 .81350 .79031 .76790 .74622 .70496 .66634 7 .87056 .84127 .81309 .78599 .75992 .73483 .71068 .66506 .62275 8 .85349 .82075 .78941 .75941 .73069 .70319 .67684 .62741 .58201 1! 1 ^ 9 .83676 .80073 .76642 .73373 .70259 .67290 .64461 .59190 .54393 10 .82035 .78120 .74409 .70892 .67556 .64393 .61391 .55839 .50835 I 11 .80426 .76214 .72242 .68495 .64958 .61620 .58468 .52679 .47509 3 12 .78849 .74356 .70138 .66178 .62460 .58966 .55684 .49697 .44401 13 .77303 .72542 .68095 .63940 .60057 .56427 .53032 .46884 .41496 4- 14 .75788 .70773 .66112 .61778 .57748 .53997 .50507 .44230 .38783 i-H 15 .74301 .69047 .64186 .59689 .55526 .51672 .48102 .41727 .36245 D 16 .72845 .67362 .62317 .57671 .53391 .49447 .4581 1 .39365 .33873 17 .71416 .65720 .60502 .55720 .51337 .47318 .43630 .37136 .31657 " 18 .70016 .64117 .58739 .53836 .49363 .45280 .41552 .35034 .29586 cj 19 .68643 .62553 .57029 .52016 .47464 .43330 .39573 .33051 .27651 3 20 .67297 .61027 .55368 .50257 .45639 .41464 .37689 .31180 .25842 jjj 25 .60953 .53939 .47761 .42315 .37512 .33273 .29530 .23300 .18425 o 30 .55207 .47674 .41199 .35628 .30832 .26700 .23138 .17411 .13137 n 40 .45289 .37243 .30656 .25257 .20829 .17193 .14205 .09722 .06678 50 .37153 .29094 .2281 1 .17905 .14071 .11071 .08720 .05429 .03395 60 .30478 .22728 .16973 .12693 .09506 .07129 .05354 .03031 .01726 Values of y'. (Interest compounded semi-annually; P = A X y') Years r = 2 2V 3 W 4 4J/2 5 6 7 1 .98030 .97546 .97066 .96590 .96117 .95647 .95181 .94260 .93351 2 .96098 .95152 .94218 .93296 .92385 .91484 .90595 .88849 .87144 3 .94205 .92817 .91454 .90114 .88797 .87502 .86230 .83748 .81350 4 .92348 .90540 .88771 .87041 .85349 .83694 .82075 .78941 .75941 .' 5 .90529 .88318 .86167 .84073 .82035 .80051 .78120 .74409 .70892 \ 6 .88745 .86151 .83639 .81206 .78849 .76567 .74356 .70138 .66178 7 .86996 .84037 .81185 .78436 .75788 .73234 .70773 .66112 .61778 8 .85282 .81975 .78803 .75762 .72845 .70047 .67362 .62317 .57671 * 9 .83602 .79963 .76491 .73178 .70016 .66998 .64117 .58739 .53836 ~Z 10 .81954 .78001 .74247 .70682 .67297 .64082 .61027 .55368 .50257 11 .80340 .76087 .72069 .68272 .64684 .61292 .58086 .52189 .46915 ^ 12 .78757 .74220 .69954 .65944 .62172 .58625 .55288 .49193 .43796 , 13 .77205 .72398 .67902 .63695 .59758 .56073 .52623 .46369 .40884 4. 14 .75684 .70622 .65910 .61523 .57437 .53632 .50088 .43708 .38165 i 15 .74192 .68889 .63976 .59425 .55207 .51298 .47674 .41199 .35628 *-* 16 .72730 .67198 .62099 .57398 .53063 .49065 .45377 .38834 .33259 n 17 .71297 .65549 .60277 .55441 .51003 .46930 .43191 .36604 .31048 *a 18 .69892 .63941 .58509 .53550 .49022 .44887 .41109 .34503 .28983 19 .68515 .62372 .56792 .51724 .47119 .42933 .39128 .32523 .27056 J2 20 .67165 .60841 .55126 .49960 .45289 .41065 .37243 .30656 .25257 s 25 .60804 .53734 .47500 .42003 .37153 .32873 .29094 .22811 .17905 30 .55045 .47457 .40930 .35313 .30478 .26315 .22728 .16973 .12693 40 .45112 .37017 .30389 .24960 .20511 .16863 .13870 .09398 .06379 50 .36971 .28873 .22563 .17642 .13803 .10806 .08465 .05203 .03206 60 .30299 .22521 .16752 .12470 .09289 .06925 .05166 .02881 .01611 MATHEMATICAL TABLES 67 Values of '. (Interest compounded quarterly; P=>A X z'', see opposite page) Years| r = 2 2tt 3 JH 4 4J4 5 6 7 1 .98025 .97539 .97055 .96575 .96098 .95624 .95152 .94218 .93296 2 .96089 .95138 .94198 .93268 .92348 .91439 .90540 .88771 .87041 3 .94191 .92796 .91424 .90074 .88745 .87437 .86151 .83639 .81206 4 .92330 .90512 .88732 .86989 .85282 .8361 1 .81975 .78803 .75762 5 .90506 .88284 .86119 .84010 .81954 .79952 .78001 .74247 .70682 \ 1-1 6 .88719 .86111 .83583 .81132 .78757 .76453 .74220 .69954 .65944 * 7 .86966 .83991 .81122 .78354 .75684 .73107 .70622 .65910 .61523 8 .85248 .81924 .78733 .75670 .72730 .69908 .67198 .62099 .57390 j 9 .83564 .79908 .76415 .73079 .69892 .66849 .63941 .58509 .53550 JL* 10 .81914 .77941 .74165 .70576 .67165 .63923 .60841 .55126 .49960 o 11 .80296 .76022 .71981 .68159 .64545 .61126 .57892 .51939 .46611 V 12 .78710 .74151 .69861 .65825 .62026 .58451 .55086 .48936 .43486 ^ 13 .77155 .72326 .67804 .63570 .59606 .55893 .52415 .46107 .40570 -j- 14 .75631 .70546 .65808 .61393 .57280 .53447 .49874 .43441 .37851 15 .74137 .68809 .63870 .59291 .55045 .51108 .47457 .40930 .35313 ' 16 .72673 .67115 .61989 .57260 .52897 .48871 .45156 .38563 .32946 II 17 .71237 .65464 .60164 .55299 .50833 .46733 .42967 .36334 .30737 %* 18 .69830 .63852 .58392 .53405 .48850 .44687 .40884 .34233 .28676 19 .68451 .62281 .56673 .51576 .46944 .42732 .38903 .32254 .26754 Js "3 20 .67099 .60748 .55004 .49810 .45112 .40862 .37017 .30389 .24960 25 .60729 .53630 .47369 .41845 .36971 .32670 .28873 .22563 .17642 o 30 .54963 .47347 .40794 .35154 .30299 .26120 .22521 .16752 .12470 40 .45023 .36903 .30255 .24810 .20351 .16697 .13702 .09235 .06230 50 .36880 .28762 .22438 .17510 .13669 .10673 .08337 .05091 .03113 60 .30210 .22417 .16641 .12358 .09181 .06823 .05072 .02806 .01555 ANNUITY WHICH WILL AMOUNT TO A GIVEN SUM (SINKING FUND) The annual payment, Y, which, if set aside at the end of each year, will amount with accumulated interest to a given sum S at the end of n years is Y = S X v', where the factor v' is given below. (Interest at r per cent, per annum, compounded annually.) Values of ' Years r= 2 2H 3 3H 4 ^ 5 6 7 2 .49505 .49383 .49261 .49140 .49020 .48900 .48780 .48544 .48309 ' 3 .32675 .32514 .32353 .32193 .32035 .31877 .31721 .31411 .31105 ^^ 4 .24262 .24082 .23903 .23725 .23549 .23374 .23201 .22859 .22523 P 5 .19216 .19025 .18835 .18648 .18463 .18279 .18097 .17740 .17389 6 .15853 .15655 .15460 .15267 .15076 .14888 .14702 .14336 .13980 '" H 7 .13451 .13250 .13051 .12854 .12661 .12470 .12282 .11914 .11555 1 8 .11651 -.11447 .11246 .11048 .10853 .10661 .10472 .10104 .09747 4, 9 .10252 .10046 .09843 .09645 .09449 .09257 .09069 .08702 .08349 10 .09133 .08926 .08723 .08524 .08329 .08138 .07950 .07587 .07238 11 .08218 .0801 1 .07808 .07609 .07415 .07225 .07039 .06679 .06336 I* 12 .07456 .07249 .07046 .06848 .06655 .06467 .06283 .05928 .05590 13 .06812 .06605 .06403 .06206 .06014 .05828 .05646 .05296 .04965 14 .06260 .06054 .05853 .05657 .05467 .05282 .05102 .04758 .04434 j* 15 .05783 .05577 .05377 .05183 .04994 .0481 1 .04634 .04296 .03979 ! 16 .05365 .05160 .04961 .04768 .04582 .04402 .04227 .03895 .03586 17 .04997 .04793 .04595 .04404 .04220 .04042 .03870 .03544 .03243 18 .04670 .04467 .04271 .04082 .03899 .03724 .03555 .03236 .02941 19 .04378 .04176 .03981 .03794 .03614 .03441 .03275 .02962 .02675 | 20 .04116 .03915 .03722 .03536 .03358 .03188 .03024 .02718 .02439 .. ^ 25 .03122 .02928 .02743 .02567 .02401 .02244 .02095 .01823 .01581 J2 " 30 .02465 .02278 .02102 .01937 .01783 .01639 .01505 .01265 .01059 l> 40 .01656 .01484 .01326 .01183 .01052 .00934 .00828 .00646 .00467 |H 50 .01182 .01026 .00887 .00763 .00655 .00560 .00478 .00344 .00238 fe 60 .00877 .00735 .00613 .00509 .00420 .00345 .00283 .00188 .00121 68 MATHEMATICAL TABLES PRESENT WORTH OF AN ANNUITY The capital C, which, if placed at interest to-day, will provide for a given annual payment Y for a term of n years before it is exhausted is C = Y X w, where the factor w is given below. (Interest at r per cent, per annum, compounded annually.) Values of w Years| r =2 2H 3 3M 4 4H 5 6 7 1 0.9804 0.9756 0.9709 0.9662 0.9615 0.9569 0.9524 0.9434 0.9346 2 1.9416 1.9274 1.9135 1.8997 1.8861 1.8727 1.8594 1.8334 1.8080 N 3 2.8839 2.8560 2.8286 2.8016 2.7751 2.7490 2.7232 2.6730 2.6243 \ 4 3.8077 3.7620 3.7171 3.6731 3.6299 3.5875 3.5460 3.4651 3.3872 1 5 4.7135 4.6458 4.5797 4.5151 4.4518 4.3900 4.3295 4.2124 4.1002 "" 6 5.6014 5.5081 5.4172 5.3286 5.2421 5.1579 5.0757 4.9173 4.7665 7 6.4720 6.3494 6.2303 6.1145 6.0021 5.8927 5.7864 5.5824 5.3893 \ 8 7.3255 7.1701 7.0197 6.8740 6.7327 6.5959 6.4632 6.2098 5.9713 * 9 8.1622 7.9709 7.7861 7.6077 7.4353 7.2688 7.1078 6.8017 6.5152 1- 10 8.9826 8.7521 8.5302 8.3166 8.1109 7.9127 7.7217 7.3601 7.0236 11 9.7868 9.5142 9.2526 9.0016 8.7605 8.5289 8.3064 7.8869 7.4987 i 12 10.575 10.258 9.9540 9.6633 9.3851 9.1186 8.8633 8.3838 7.9427 13 11.348 10.983 10.635 10.303 9.9856 9.6829 9.3936 8.8527 8.3577 I 14 12.106 11.691 11.296 10.921 10.563 10.223 9.8986 9.2950 8.7455 \ 15 12.849 12.381 11.938 11.517 11.118 10.740 10.380 9.7122 9.1079 ^ 16 13.578 13.055 12.561 12.094 11.652 11.234 10.838 10.106 9.4466 + 17 1 4.292 13.712 13.166 12.651 12.166 11.707 11.274 10.477 9.7632 18 14.992 14.353 13.754 13.190 12.659 12.160 11.690 10.828 10.059 Zl 19 15.678 14.979 14.324 13.710 13.134 12.593 12.085 11.15.8 10.336 1 20 16.351 15.589 14.877 14.212 13.590 13.008 12.462 11.470 10.594 a ^ 25 19.523 18.424 17.413 16.482 15.622 14.828 14.094 12.783 11.654 3 T 30 22.396 20.930 19.600 18.392 17.292 16.289 15.372 13.765 12.409 s " 40 27.355 25.103 23.115 21.355 19.793 18.402 17.159 15.046 13.332 o 5 50 31.424 28.362 25.730 23.456 21.482 19.762 18.256 15.762 13.801 HH 60 34.761 30.909 27.676 24.945 22.623 20.638 18.929 16.161 14.039 ANNUITY PROVIDED FOR BY A GIVEN CAPITAL The annual payment Y provided for for a term of n years by a given capital C placed at interest to-day is Y = C X w' . (Interest at r per cent, per annum, compounded annually; the fund supposed to be exhausted at the end of the term.) Values of w' Years r = 2 2% 3 3H 4 4H 5 6 7 2 .51505 .51883 .52261 .52640 .53020 .53400 .53780 .54544 .55309 3 .34675 .35014 .35353 .35693 .36035 .36377 .36721 .37411 .38105 4 .26262 .26582 .26903 .27225 .27549 .27874 .28201 .28859 .29523 c; 5 .21216 .21525 .21835 .22148 .22463 .22779 .23097 .23740 .24389 6 .17853 .18155 .18460 .18767 .19076 .19388 .19702 .20336 .20980 C^ 7 .15451 .15750 .16051 .16354 .16661 .16970 .17282 .17914 .18555 ^ 8 .13651 .13947 .14246 .14548 .14853 .15161 .15472 .16104 .16747 _i_ X. 9 .12252 .12546 .12843 .13145 .13449 .13757 .14069 .14702 .15349 ^ 10 .11133 .11426 .11723 .12024 .12329 .12638 .12950 .13587 .14238 _ TH 11 .10218 .10511 .10808 .11109 .11415 .11725 .12039 .12679 .13336 1 xb 12 .09456 .09749 .10046 .10348 .10655 .10967 .11283 .11928 .12590 ~ + 13 .08812 .09105 .09403 .09706 .10014 .10328 .10646 .11296 .11965 14 .08260 .08554 .08853 .09157 .09467 .09782 .10102 .10758 .11434 1' v e 15 .07783 .08077 .08377 .08683 .08994 .09311 .09634 .10296 .10979 Ii 16 .07365 .07660 .07961 .08268 .08582 .08902 .09227 .09895 .10586 17 .06997 .07293 .07595 .07904 .08220 .08542 .08870 .09544 .10243 ^T ^ 18 .06670 .06967 .07271 .07582 .07899 .08224 .08555 .09236 .09941 II II 19 .06378 .06676 .06981 .07294 .07614 .07941 .08275 .08962 .09675 20 .06116 .06415 .06722 .07036 .07358 .07688 .08024 .08718 .09439 9 25 .05122 .05428 .05743 .06067 .06401 .06744 .07095 .07823 .08581 30 .04465 .04778 .05102 .05437 .05783 .06139 .06505 .07265 .08059 "5 40 .03656 .03984 .04326 .04683 .05052 .05434 .05828 .06646 .07467 g 50 .03182 .03526 .03887 .04263 .04655 .05060 .05478 .06344 .07238 60 .02877 .03235 .03613 .04009 .04420 .04845 .05283 .06188 .07121 fc MATHEMATICAL TABLES DECIMAL EQUIVALENTS From minutes and From decimal parts of Common fractions seconds into deci- mal parts of a degree a degree into minutes and seconds (exact values) 8 16 32 64 ths ths nds ths Exact decimal values 0' o.oooo 0" o.oooo o.oo 0' 0.50 30' 1 .01 5625 1 .0167 1 .0003 1 0' 36" 1 30' 36" 1 2 .03 125 2 .0333 2 .0006 2 1' 12" 2 31' 12" 3 .04 6875 3 .05 3 .0008 3 V 48" 3 31' 48" 1 2 4 .06 25 4 .0667 4 .0011 4 2' 24" 4 32' 24" 5 .07 8125 5' .0833 5" .0014 0.05 3' 0.55 33' 3 6 .09 375 6 .10 6 .0017 6 y 36" 6 33' 36" 7 .10 9375 7 .1167 7 .0019 7 4' 12" 7 34' 12" 1248 .12 5 8 .1333 8 .0022 8 4' 48" 8 34' 48" 9 .14 0625 9 .15 9 .0025 9 5' 24" 9 35' 24" 5 10 .15 625 10' 0.1667 10" 0.0028 0.10 6' 0.60 36' 11 .17 1875 1 .1833 ] .0031 1 6' 36" 1 36' 36" 3 6 12 .18 75 2 .20 2 .0033 2 7' 12" 2 37' 12" 13 .20 3125 3 .2167 3 .0036 3 7' 48" 3 37' 48" 7 14 .21 875 4 .2333 4 .0039 4 8' 24" 4 38' 24" 15 .23 4375 15' .25 15" .0042 0.15 9' 0.65 39' 2 4 8 16 .25 6 .2667 6 .0044 6 9' 36" 6 39' 36" 17 .26 5625 7 .2833 7 .0047 7 10' 12" 7 40' 12" 9 18 .28 125 8 .30 8 .005 8 10' 48" 8 40' 48" 19 .29 6875 9 .3167 9 .0053 9 11' 24" 9 41' 24" 5 10 20 .31 25 20' 0.3333 20" 0.0056 0.20 12' 0.70 42' 21 .32 8125 1 .35 1 .0058 12' 36" 42' 36" 11 22 .34 375 2 .3667 2 .0061 2 13' 12" 2 43' 12" 23 .35 9375 3 .3833 3 .0064 3 13' 48" 3 43' 48" 3 6 12 24 .37 5 4 .40 4 .0067 4 14' 24" 4 44' 24" 25 .39 0625 25' .4167 25" .0069 0.25 15' 0.75 45' 13 26 .40 625 6 .4333 6 .0072 6 15' 36" 6 45' 36" 27 .42 1875 7 .45 7 .0075 7 16' 12" 7 46' 12" 7 14 28 .43 75 8 .4667 8 .0078 8 16' 48" 8 46' 48" 29 .45 3125 9 .4833 9 .0081 9 17' 24" 9 47' 24" 15 30 .46 875 30' 0.50 30" 0.0083 0.30 18' 0.80 48' 31 .48 4375 1 .5167 1 .0086 1 18' 36" 1 48' 36" 4 8 16 32 .50 2 .5333 2 .0089 2 19' 12" 2 49' 12" 33 .51 5625 3 .55 3 .0092 3 19' 48" 3 49' 48" 17 34 .53 125 4 .5667 4 .0094 4 20' 24" 4 50' 24" 35 .54 6875 35' .5833 35" .0097 0.35 21' 0.85 51' 9 18 36 .56 25 6 .60 6 .01 6 21' 36" 6 51' 36" 37 .57 8125 7 .6167 7 .0103 7 22' 12" 7 52' 12" 19 38 .59 375 8 .6333 8 .0106 8 22' 48" 8 52' 48" 39 .60 9375 9 .65 9 .0108 9 23' 24" 9 53' 24" 5 10 20 40 .62 5 40' 0.6667 40" 0.01 1 1 0.40 24' 0.90 54' 41 .64 0625 1 .6833 1 .0114 1 24' 36" 54' 36" 21 42 .65 625 2 .70 2 .0117 2 25' 12" 2 55' 12" 43 .67 1875 3 .7167 3 .0119 3 25' 48" 3 55' 48" 11 22 44 .68 75 4 .7333 4 .0122 4 26' 24" 4 56' 24" 45 .70 3125 45' .75 45" .0125 045 27' 0.95 57' 23 46 .71 875 6 .7667 6 .0128 6 27' 36" 6 57' 36" 47 .73 4375 7 .7833 7 .0131 7 28' 12" 7 58' 12" 6 12 24 48 .75 8 .80 8 .0133 8 28' 48" 8 58' 48" 49 .76 5625 9 .8167 9 .0136 9 29' 24" 9 59' 24" 25 50 .78 125 50' 0.8333 50" 0.0139 0.50 30' 1.00 60' 51 .79 6875 1 .85 .8667 1 2 .0142 .0144 o.ooo 0".0 13 26 52 53 .81 25 .82 8125 3 .8833 3 .0147 1 3".6 27 54 .84 375 4 .90 4 .015 2 7".2 55 .85 9375 55' .9167 55" .0153 3 10".8 7 14 28 56 .87 5 6 .9333 6 .0156 4 14".4 57 .89 0625 7 .95 7 .0158 0.005 18" 29 58 .90 625 8 .9667 8 .0161 6 21".6 59 .92 1875 9 .9833 9 .0164 7 25".2 15 30 60 .93 75 60' 1.00 60" 0.0167 8 28".8 61 .95 3125 9 32" .4 31 62 .96 875 0.010 36" 63 .98 4375 WEIGHTS AND MEASURES BY LOUIS A. FISCHER In the United States the measures of weight and length commonly employed are identical with the corresponding English units, but the capacity measures differ from those now in use in the British Empire, the U. S. gallon being defined as 231 cu. in. and the bushel as 2150.42 cu. in., whereas the corre- sponding British imperial units are, respectively, 277.418 cu. in., and 2219.344 cu. in. (1 imp. gal. = 1.2 U. S. gal., approx.; 1 imp. bu. = 1.03 U. S. bu., approx.). The metric system of weights and measures was legalized and its use made permissive in the United States by an Act of Congress, passed in 1866. In 1872, by the concurrent action of the principal governments of the world, it was agreed to establish an International Bureau of Weights and Measures near Paris. Prior to 1891 the British imperial yard was regarded as the real standard of the United States. In 1891, the Office of Weights and Measures (now Bureau of Standards) fixed the value of the United States yard in terms of the international meter, according ito the ratio: one yard = 3600/3937 meters. At the same time, the pound was fixed in terms of the international kilo- gram, according to the relation: one pound = 453.59243 grams. U. S. Customary Weights and Measures Measures of Length Measures of Area 12 inches 3 feet 5H yards = 16^ feet 40 poles = 220 yards 8 furlongs = 1760 yards = 5280 feet 3 miles 4 inches 9 inches = 1 foot = 1 yard = 1 rod, pole or perch = 1 furlong = 1 mile = 1 league = 1 hand = 1 span = 1 acre 640 acres = 1 square mile = Nautical Units 6080.2 feet = 1 nautical mile 6 feet = 1 fathom 120 fathoms = 1 cable length 1 nautical mile per hr. = 1 knot Surveyor's or Gunter's Measure 7.92 inches = 1 link 100 links = 66 ft. = 4 rods = 1 chain 80 chains = 1 mile 33H inches = 1 vara (Texas) 144 square inches = 1 square foot 9 square feet = 1 square yard 30^4 square yards = 1 square rod, pole or perch 160 square rods = 10 square chains = 43,560sq. ft, = 5645 sq. varas (Texas) 1 ''section" of U. S. Govt. surveyed land 1 circular inch = area of circle 1 inch in diameter 1 square inch = 1.2732 cir. in. 1 circular mil =area of circle 0.001 in. in diam. 1,000,000 cir. mils = l cir. in. Measures of Volume 1728 cubic inches = 1 cubic foot 27 cubic feet = 1 cubic yard 1 cord of wood =128 cu. ft. 1 perch of masonry = 16K> to 25 cu. ft. = 0.7854 sq. in. 70 U. S. WEIGHTS AND MEASURES 71 U. S. Customary Weights and Measures (continued) Measures of Volume Weights (The grain is the same in all systems) Liquid or Fluid Measure 4 gills = 1 pint 2 pints = 1 quart 4 quarts <= 1 gallon 7.4805 gallons = 1 cubic foot (There is no standard liquid "barrel.") Apothecaries' Liquid Measure 60 minims = 1 liquid dram or drachm 8 drams = 1 liquid ounce 16 ounces = 1 pint Water Measure The Miner's Inch is the quantity of water that will pass through an orifice 1 sq. in. in cross-section under a head of from 4 to 6^ in., as fixed by statutes, and varies from Ho cu. ft. to Ho cu. ft. per sec. The units now most in use are 1 cu. ft. per sec. and 1 gal. per sec., the U. S. Reclamation Service employing the former. See p. 260. Dry Measure 2 pints = 1 quart 8 quarts = 1 peck 4 pecks = 1 bushel Shipping Measure 1 Register ton = 100 cu. ft. 1 U. S. shipping ton = 40 cu. ft. = f 32.14 U. S. bu. m 131.14 imp. bu. 1 British shipping ton = 42 cu. ft. / 32.70 imp. bu. ~ \ 33.75 U. S. bu. Board Measure ( 144 cu. in. = volume of 1 board foot = { board 1 ft. sq. and 1- in. i thick. No. of board feet in a log = [\i(d - 4)pZ,, where d = diam. of log (usually taken in- side the bark at small end), in., and L = length of log, ft. The 4 in. deducted are an allowance for slab. This rule is vari- ously known as the Doyle, Conn. River, St. Croix, Thurber, Moore and Beeman, and the Scribner rule. Avoirdupois Weight 16 drams = 437.5 grains = 1 ounce 16 ounces = 7000 grains = 1 pound 100 pounds <= 1 cental 2000 pounds = 1 short ton 2240 pounds *= 1 long ton Also (in Great Britain): 14 pounds 2 stone = 28 Ib. 4 quarters = 1 12 Ib. 20 hundredweight = 1 stone = 1 quarter = 1 hundred- weight (cwt.) = 1 long ton 24 grains Troy Weight = 1 penny- weight (dwt.) 20 pennyweights = 480 grains = 1 ounce 12 ounces = 5760 grains =1 pound 1 Assay Ton = 29,167 milligrams, or as many milligrams as there are troy ounces in a ton of 2000 Ib. avoirdupois. Consequently, the number of milligrams of precious metal yielded by an assay ton of ore gives directly the number of troy ounces that would be obtained from a ton of 2000 Ib. avoirdupois. Apothecaries' Weight 20 grains = 1 scruple 3 3 scruples = 60 grains = 1 dram 3 8 drams = 1 ounce 5 12 ounces = 5760 grains = 1 pound Weight for Precious Stones 1 carat = 200 milligrams (Adopted by practically all important nations.) Circular Measure 60 seconds = 1 minute 60 minutes = 1 degree 90 degrees = 1 quadrant 360 degrees = circumference 57.2957795 degrees =1 radian (or angle ( = 57 17'44.806") having arc of length equal to radius) METRIC SYSTEM The fundamental unit of the metric system is the meter the unit of length, from which the units of volume (liter) and of mass (gram) are derived. All other units are the decimal subdivisions or multiples of these. These three units are simply related : one cubic decimeter equals one liter, and one liter of water weighs one kilogram. The metric tables are formed by combining the words "meter," "gram," and "liter" with numerical prefixes. 72 WEIGHTS AND MEASURES All lengths, areas, and cubic measures in the following conversion tables are derived from the international meter. The customary weights are like- wise derived from the kilogram. All capacities are based on the practical equivalent: 1 cubic decimeter equals 1 liter. (The liter is defined as the volume occupied by the mass of 1 kilogram of water under a pressure of 76 cm. of mercury and at the temperature of 4 deg. cent. According to the best information, 1 liter = 1.000027 cubic decimeters.) The customary weights derived from the international kilogram are based on the value 1 avoirdupois Ib. = 453.59243 grams. The value of the troy ib. is based on the same relation and also the equivalent 5760/7000 avoirdupois Ib. equals 1 troy Ib. Metric Measures Length Area Unit Sym- bol Value in meters Unit Sym- bol Value in sq. meters Micron M mm. cm. dm. m. dkm. hm. km. Mm. 0.000001 0.001 0.01 0.1 1.0 10.0 100.0 1,000.0 10,000.0 1,000,000.0 Millimeter.... Centimeter . . Decimeter. . . Meter (unit). Dekameter. . Hectometer.. Kilometer. . . Myriameter.. . Megameter.. . Sq. millimeter mm. 2 cm. 2 dm. 2 m. a. ha. km." . 000001 0.0001 0.01 1.0 100.0 10,000.0 1,000,000.0 Sq. centimeter Sq. decimeter Sq. meter (centiare) Sq. dekameter (are) Hectare Sq. kilometer. . Volume Cubic measure Unit Symbol Value in liters Unit Symbol Value in cubic meters Milliliter Liter (unit) ml. or cm. 3 1. or dm. 8 kl. or m.s cl. dl. dkl. hi. 0.001 1.0 1,000.0 0.01 0.1 10.0 100.0 Cubic kilometer Cubic hectometer. . . . Cubic dekameter Cubic meter Cubic decimeter Cubic centimeter Cubic millimeter Cubic micron km. 3 hm. dkm. s m.8 dm. 3 cm. 3 mm. 3 M 8 10 10 10 3 1 10- 10" ID' 9 10-18 Kiloliter Also Centiliter Deciliter Dekaliter Hectoliter Weight Unit Symbol Value in grams Unit Symbol Value in grams Microgram 0.000001 Dekagram dkg. 10.0 Milligram mg. 0.001 Hectogram fag 100 Centigram Decigram eg- dg. 0.01 0.1 Kilogram Myriagram kg. Mg 1,000.0 10,000 Gram (unit) 1 100 000 Ton t. 1,000,000.0 SYSTEMS OF UNITS The principal, units of interest to mechanical engineers can all be derived from the three fundamental units of force, length, and time. These three fundamental units may be chosen at pleasure; each such choice gives rise to a "system" of units. The following table gives the units of the four "systems" most often met with in the literature. UNITS 73 The precise definitions of the fundamental units in these systems are as follows. (In these definitions the "standard pound body " and the "standard kilogram body "refer to two special lumps of metal, carefully preserved at London and Paris, respectively; the "standard locality" means sea level, 45 deg. latitude; or, more strictly, any locality in which the acceleration due to gravity has the value 980.665 cm. per sec. 2 = 32.1740 ft. per sec. 2 , which may be called the standard acceleration. The pound (force) is the force required to support the standard pound body against gravity, in vacua, in the standard locality; or, it is the force which, if applied to the stand- ard pound body, supposed free to move, would give that body the "standard ac- celeration." The word "pound" is used for the unit of both force and mass, and consequently is ambiguous. To avoid uncertainty it is desirable to call the units "pound force" and "pound mass," respectively. The kilogram (force) is the force required to support the standard kilogram against gravity, in vacua, in. the standard locality; or, it is the force which, if applied to the stand- ard kilogram body, supposed free to move, would give that body the "standard accelera- tion." The word "kilogram" is used for the unit of both force and mass and conse- quently is ambiguous. To avoid uncertainty it is desirable to call the units "kilogram force" and "kilogram mass," respectively. The poundal is the force which, if applied to the standard pound body, would give that body an acceleration of 1 ft. per sec. 2 ; that is, 1 poundal = 1/32.1740 of a pound force. The dyne is the force which, if applied to the standard gram body, would give that body an acceleration of 1 cm. per sec. 2 ; that is, 1 dyne = 1/980.665 of a gram force. Systems of Units British Metric Name of unit Dimen- sions of units in terms of F,L, T "gravita- tional " sys- tem, or "foot-pound- second" "gravita- tional " sys- tem, or "kilogram- meter-sec- Metric "absolute" system, or "C. G. S." system British "absolute" system (little used) system ond" system Force F 1 Ib. 1 kg. 1 dyne 1 poundal Length L 1 ft. 1 m. 1 cm. 1ft. Time T 1 sec. 1 sec. 1 sec. 1 sec. Velocity Acceleration . . L/T L/T* 1 ft. per sec. 1 ft. per sec. 2 1 m. per sec. 1 m. per sec. 2 1 cm. per sec. 1 cm. per sec. 2 1 ft. per sec. 1ft. per sec. 2 Pressure F/L* lib. per ft. 2 1 kg. per m. 2 1 dyne per cm. 2 1 pdl. per ft. 2 Impulse or momentum. . FT 1 Ib.-sec. 1 kg.-sec. 1 dyne-sec. 1 pdl.-sec. Work or energy FL 1 ft.-lb. 1 kg.-m. 1 dyne-cm. = 1 ft. -pdl. 1 "erg." Power FL/T 1 ft.-lb. per 1 kg.-m. per 1 dyne-cm, per 1 ft.-pdl. per sec. sec. sec. sec. Mass F/(L/T*) 1 Ib. per (ft. 1 kg. per (m. 1 dyne per (cm. 1 pdl. per (ft. per sec. 2 ) = per sec. 2 ) = per sec. 2 ) = 1 per sec. 2 ) = 1 "slug." 1 " metric gram mass. 1 pound slug." mass. NOTE. The "slug" (also called the "geepound," or the "engineer's unit of mass"), the " metric slug," and the "poundal" are never used in practice. Other common units are as follows: Work: 1 joule = 10? ergs = 10,000,000 dyne-cm. 1 kilowatt-hour = 3,600,000 joules = 3600 X lO dyne-cm. Power: 1 horse power = 550 ft.-lb. per sec. 1 poncelet = 100 kg.-m. per sec. 1 force de cheval = 75 kg.-m. per sec. 1 watt = 1 joule per sec. = 10,000,000 dyne-cm, per sec. 1 kilowatt = 1000 watts = 10 10 dyne-cm, per sec. A new horse power of 550.220 ft.-lb. per sec., or 746 watts, has been proposed, but has not been accepted by mechanical engineers. The weight of a body (in a given locality) always means a force, namely, the force, re- 74 WEIGHTS AND MEASURES quired to support the body against gravity (in that locality). 'When no particular local- ity is specified, the standard locality may be assumed. Thus, the "standard weight" of the pound body is 1 lb.; the "standard weight" of the kilogram body is 1 kg Dynes X 10 Kilograms Pounds Poundala the quantity of heat required to raise the temperature of 1 gram of water 1 deg. cent, at a mean temperature of 15 deg. cent., or (2) the heat required to raise the temperature of 1 lb. of water 1 deg. fahr. The former quantity is called the gram-calorie (small calorie), while the latter is known as the British thermal unitorB.t.u. The kilogram-calorie (large calorie), which ia equal to 1000 g.-cal., is largely used in engineering work in metric countries. * 1 therm = 1 g.-cal. CONVERSION TABLES Length Equivalents 1 1.020 0.00848 2.248 ' 0.03518 72.33 1.85933 0.9807 1.99149 1 2.205 0.34334 70.93 1.85C84 0.4448 1.64819 0.4536 1.65667 1 32.17 1.50750 0.01383 2.14067 0.01410 2.14916 0.03108 2.49249 1 Centimeters Inches Feet | Yards | Meters Chains Kilometers Miles 1 0.3937 1.59517 0.03281 2.51598 0.01094 2.03886 0.01 2.00000 0.0 3 497I 4.69644 10-5 B". 00000 0.0 6 6214 6.79335 2.540 0.40483 1 0.0 3 8333 4.92082 0.02778 2.44370 0.0254 2.40483 0.0*1263 5.10127 0.0 4 254 5.40483 0.041578 5.19818 30.48 1.48402 12 1.07918 1 0.3333 T.52288 0.3048 1.48402 0.01515 2.18046 0.0 3 3098 4.48402 0.0s 1645 4.21608 91.14 1.96114 36 1.55630 3 0.47712 1 0.9144 1.96114 0.04545 2.65758 0.0s9144 4.96114 0.0 3 5682 4.75449 100 2.00000 39.37 1.59517 3.281 0.51598 1 .0936 0.03886 1 0.04971 2.69644 0.001 3.COOOO 0.0 3 62!4 4.79335 2012 3.30356 792 2.89873 66 1.81954 22 1.34242 20.12 1.30356 1 0.02012 2.30356 0.0125 2.09691 100000 5.00000 39370 4.59517 3281 3.51598 1093.6 3.C3886 1000 3.00000 49.71 1.69644 1 0.6214 1.79335 160925 5.20665 63360 4.80182 5280 3.72263 1760 3.24551 1609 3.20665 80 1.90309 1.609 0.206G5 1 The equivalents are given in the heavier type. Logarithms of the equivalents are given immediately below. Subscripts after any figure, Os, 94, etc.J mean that that figure is to be repeated the indicated number of times. Conversion of Lengths Inches to milli- meters Milli- meters to inches Feet to meters Meters to feet Yards to meters Meters to yards Miles to kilo- meters Kilo- meters to miles 1 3 4 6 7 [ 25.40 50.80 76.20 101 .60 127.00 152.40 177.80 203.20 228.60 0.03937 0.07874 0.1181 0.1575 0.1968 0.2362 0.2756 0.3150 0.3543 0.3048 0.6096 0.9144 1.219 1.524 1.829 2.134 2.438 2.743 3.281 6.562 9.842 13.12 16.40 19.68 22.97 26.25 29.53 0.9144 1.829 2.743 3.658 4.572 5.486 6.401 7.315 8.230 1.094 2.187 3.281 4.374 5.486 6.562 7.655 8.749 9.842 1.609 3.219 4.828 6.437 8.047 9.656 . 11.27 12.87 14.48 0.6214 1.243 1.864 2.485 3.107 3.728 4.350 4.971 5.592 *See Marks' MECHANICAL ENGINEERS' HANDBOOK.. CONVERSION TABLES 75 Mechanical Equivalent of Heat. See p. 311.* The value most commonly accepted among American engineers as the work equivalent of 1 mean B.t.u. is 777.5 ft.-lb., and the mean gram-calorie = 4.183 joules, which are the values used throughout this book. The U. S. Bureau of Standards does not recommend any special value; for its own purposes it takes the 59 deg. fahr. B.t.u. as 778.2 ft.-lb. and the 68 deg. B.t.u. as 777.5 ft.-lb. The 15 deg. calorie = 4.187 joules; 20 deg. calorie = 4.183 joules. There is an uncer- tainty of about 1 part in 1000 in these values. Conversion of Lengths : Inches and Millimeters Common fractions of an inch to millimeters (From HU to 1 in.) 64ths Milli- meters 64ths Milli- meters 64ths Milli- meters 64ths Milli- meters 64ths Milli- meters 64ths Milli- meters 1 0.397 13 5.159 25 9.922 37 14.684 49 19.447 57 22.622 2 0.794 14 5.556 26 10.319 38 15.081 50 19.844 58 23.019 3 1.191 15 5.953 27 10.716 39 15.478 51 20.241 59 23.416 4 1.588 16 6.350 28 11.113 40 15.875 52 20.638 60 23.813 5 1.984 17 6.747 29 11.509 41 16.272 53 21.034 61 24.209 6 2.381 18 7.144 30 11.906 42 16.669 54 21.431 62 24.606 7 2.778 19 7.541 31 12.303 43 17.066 55 21.828 63 25.003 8 3.175 20 7.938 32 12.700 44 17.463 56 22.225 64 25.400 9 3.572 21 8.334 33 13.097 45 17.859 10 3.969 22 8.731 34 13.494 46 18.256 11 4.366 23 9.128 35 13.891 47 18.653 12 4.763 24 9.525 36 14.288 48 19.050 Decimals of an inch to millimeters. (From 0.01 in. to 0.99 in.) 1 2 3 4 5 6 7 8 9 .0 0.254 0.508 0.762 1.016 1.270 1.524 1.778 2.032 2.286 .1 2.540 2.794 3.048 3.302 3.556 3.810 4.064 4.318 4.572 4.826 .2 5.080 5.334 5.588 5.842 6.096 6.350 6.604 6.858 7.112 7.366 .3 7.620 7.874 8.128 8.382 8.636 8.890 9.144 9.398 9.652 9.906 .4 10.160 10.414 10.668 10.922 11.176 11.430 11.684 11.938 12.192 12.446 .5 12.700 12.954 13.208 13.462 13.716 13.970 14.224 14.478 14.732 14 986 .6 15.240 15.494 15.748 16.002 16.256 16.510 16.764 17.018 17.272 17.526 .7 17.780 18.034 18.288 18.542 18.796 19.050 19.304 . 19.558 19.812 20.066 .8 20.320 20.574 20.828 21 .082 21.336 21.590 21 .844 22.098 22.352 22.606 .9 22.860 23.114 23.368 23.622 23.876 24.130 24.384 24.638 24.892 25.146 Millimeters to decimals of an inch. (From 1 to 99 mm.) 0. 1. 2. 3. 4. 5. 6. 7. 8. 9. 0.0394 0.0787 0.1181 0.1575 0.1969 0.2362 0.2756 0.3150 0.3543 1 0.3937 0.4331 0.4724 0.5118 0.5512 0.5906 0.6299 0.6693 0.7087 0.7480 2 0.7874 0.8268 0.8661 0.9055 0.9449 0.9843 1 .0236 1 .0630 1.1024 1.1417 3 1.1811 1.2205 1 .2598 1.2992 1.3386 1.3780 1.4173 1.4567 1 .4961 1.5354 4 1.5748 1.6142 1 .6535 1 .6929 1.7323 1.7717 1.8110 1.8504 1.8898 1.9291 5 1.9685 2.0079 2.0472 2.0866 2.1260 2.1654 2.2047 2.2441 2.2835 2.3228 6 2.3622 2.4016 2.4409 2.4803 2.5197 2.5591 2.5984 2.6378 2.6772 2.7165 7 2.7559 2.7953 2.8346 2.8740 2.9134 2.9528 2.9921 3.0315 3.0709 3.1102 8 3.1496 3.1890 3.2283 3.2677 3.3071 3.3465 3.3858 3.4252 3.4646 3.5039 9 3.5433 3.5827 3.6220 3.6614 3.7008 3.7402 3.7795 3.8189 3.8583 3.8976 'See Marks' MECHANICAL ENGINEERS' HANDBOOK. 76 WEIGHTS AND MEASURES Area Equivalents (For conversion table see p. 77) Square meters Square inches Square feet Square yards Square rods Square chains Roods Acres Square miles or sections 1 1550 3.19033 10.76 1.03197 1.196 0.07773 0.0395 2.59699 0.002471 3.39288 0.0 3 9884 3.99494 0.0>2471 1.39288 0.0*3861 7.58670 0.0 3 6452 4 80967 1 0.006944 3.84164 0.0011 3.88740 0.042551 5.40667 0.0*1594 6.20255 6 6377 7.80461 0.0e1594 7.20255 0.0 8 4910 10.39637 0.09290 1.96803 144 2.15836 1 0.1111 1.04576 0.003673 3.56503 0.0 3 2296 4.36091 0.049184 5.96297 0.0 4 2296 4.36091 0.0:3587 "S. 554 73 0.8361 1.92227 1296 3.11260 9 0.95424 1 0.03306 2.51927 0.002066 3.31515 0.0 3 8264 4.91721 0.0002066 4.31515 0.0 6 3228 7.50898 25.29 1.40300 39204 4.59333 272.25 2.43497 30.25 1.48072 1 0.0625 2.79588 0.02500 2.39794 0.00625 3.79588 0. 0*9766 6.98970 404.7 2.60712 627264 5.79745 4356 3.63909 484 2.68484 16 1.20412 1 0.4 1.60206 0.1 1.00000 0.0001562 4.19382 1012 3.00506 1568160 6.19539 10890 4.03703 1210 3.08278 40 1.60206 2.5 0.39794 1 0.25 1.39794 0.0 3 3906 "4.59176 4047 3.60712 6272640 6.79745 43560 4.63909 4840 3.68484 160 2.20412 10 1.00000 4 0.60206 1 0.001562 3.19382 2589a8 6.41330 27878400 7.44527 3097600 6.49102 102400 5.01030 6400 3.80618 2560 3.40824 640 2.80618 1 (1 hectare =100 ares = 10,000 centiares or square meters) Volume and Capacity 'Equivalents (For conversion table see p. 77) Cubic inches Cubic feet Cubic yards U. S. Apothe- cary liquid ounces U. S. quarts U. S. gallons Bushels U. S. Liters (1) Liquid ry Liquid Dry 1 0.0 3 5787 4.76246 0.0 4 2143 F. 33109 0.5541 1. 74360 0.01732 2.23845 0.01488 2.17263 0.0 2 4329 3.63639 0.0 2 3720 3.57057 0.0 3 4650 4.66748 0.01639 2.21450 1728 3.23754 1 0.03704 2". 56864 957.5 2.98114 29.92 1.47599 25.71 1.41017 7.481 0.87393 6.429 0.80811 0.8036 1.90502 28.32 1.45205 46656 4.66891 1.805 0.25640 27 . 1.43136 001044 3.01886 1 0.0 4 3868 5.58749 25853 4.41251 1 807.9 2.90736 0.03125 2.49485 694.3 2.84153 0.02686 2.42903 202.0 2.30530 0.007813 3.89279 173.6 2.23948 0.006714 3.82697 21.70 1.33638 0.0 3 8392 4.92388 764.6 2.88341 0.02957 2.47091 57.75 1.76155 0.03342 2.52401 0.001238 3.09264 32 1.50515 1 0.8594 1.93418 0.25 1.39794 0.2148 1.33212 0.02686 2.42903 0.9464 1.97606 67.20 1.82737 0.03889 2.58983 0.001440 3.15847 37.24 1.57097 1.164 0.06582 1 2909 1.46376 0.25 1.39794 0.03125 2.49485 1.101 0.04188 231 2.36361 0.1337 1.12607 0.004951 3.69470 128 2.10721 4 0.60206 3.437 0.53624 1 0.8594 1.93418 0.1074 1.03109 3.785 0.57812 268.8 2.42943 0.1556 1.19189 0.005761 3.76053 148.9 2.17303 4.655 0.66788 4 0.60206! 1.164 0.06582 1 0.125 1.09691 4.405 0.64394 2150 3.33252 1.244 0.09498 0.04609 2.66362 1192 3.07612 37.24 1.57097 32 1.50515 9.309 0.96891 8 0.90309 1 35.24 1.54703 61.02 1.78550 0.03531 2.54795 0.001308 3.11659 33.81 1.52909 1.057 0.02394 0.9081 1.95812 0.2642 L 42188 0.2270 1.35606 02838 2.45297 1 The equivalents are given in the heavier type. Logarithms of the equivalents are given immediately below. Subscripts after any figure, Oa, 94, etc., mean that that figure ia to be repeated the indicated number of timeB. CONVERSION TABLES 77 Conversion of Areas Sq. in. to sq. cm. Sq. cm. to sq. in. Sq. ft. to sq. m. Sq. m. to sq. ft. Sq. yd. to sq. m. Sq. m. to sq. yd. Acres to hec- tares Hec- tares to acres Sq. mi. to sq. km. Sq. km. to sq. mi. 1 2 3 4 5 6 7 8 9 6.452 12.90 19.35 25.81 32.26 38.71 45.16 51.61 58.06 0.1550 0.3100 0.4650 0.6200 0.7750 0.9300 1.085 1.240 1.395 0.0929 0.1858 0.2787 0.3716 0.4645 0.5574 0.6503 0.7432 0.8361 10.76 21.53 32.29 43.06 53.82 64.58 75.35 86.11 96.87 0.8361 1.672 2.508 3.345 4.181 5.017 5.853 6.689 7.525 1.196 2.392 3.588 4.784 5.980 7.176 8.372 9.568 10.764 0.4047 0.8094 1.214 1.619 2.023 2.428 2.833 3.237 3.642 2.471 4.942 7.413 9.884 12.355 14.826 17.297 19.768 22.239 2.590 5.180 7.770 10.360 12.950 15.540 18.130 20.720 23.310 0.3861 0.7722 1.158 1.544 1.931 2.317 2,703 3.089 3.475 Conversion of Volumes or Cubic Measure Cu. in. to cu. cm. Cu. cm. to cu. in. Cu. ft. to cu. m. Cu. m. to cu. ft. Cu. yd. to Cu. m. Cu. m. to cu. yd. Gallons to cu. ft. Cu. ft. to gallons 2 3 4 5 6 7 8 9 16.39 32.77 49.16 65.55 81.94 98.32 114.7 131.1 147.5 0.06102 0.1220 1831 0.2441 0.3051 0.3661 0.4272 0.4882 0.5492 0.02832 0.05663 0.08495 0.1133 0.1416 0.1699 0.1982 0.2265 0.2549 35.31 70.63 105.9 141.3 176.6 211.9 247.2 282.5 317.8 0.7646 1.529 2.294 3.058 3.823 4.587 5.352 6.116 6.881 1.308 2.616 3.924 5.232 6.540 7.848 9.156 10.46 11.77 0.1337 0.2674 0.4011 0.5348 0.6685 0.8022 0.9359 1.070 1.203 7.481 14.96 22.44 29.92 37.41 44.89 52.36 59.85 67.33 Conversion of Volumes or Capacities Liquid ounces to cu. cm. Cu. cm. to liquid ounces Pints to liters Liters to pints Quarts to liters Liters to quarts Gallons to liters Liters to gallons Bushels to hecto- liters Hecto- liters to bushels 1 29.57 0.03381 0.4732 2.113 0.9464 1.057 3.785 0.2642 "0.3524 2.838 2 59.15 0.06763 0.9464 4.227 1.893 2.113 7.571 0.5283 0.7048 5.676 3 88.72 0.1014 1.420 6.340 2.839 3.170 11.36 0.7925 1.057 8.513 4 118.3 0.1353 1.893 8.453 3.785 4.227 15.14 1 .057 1.410 11.35 5 147.9 0.1691 2.366 10.57 4.732 5.283 18.93 1.321 1.762 14.19 6 177.4 0.2029 2.839 12.68 5.678 6.340 22.71 1.585 2.114 17.03 7 207.0 0.2367 3.312 14.79 6.625 7.397 26.50 1.849 2.467 19.86 8 236.6 0.2705 3.785 16.91 7.571 8.453 30.28 2.113 2.819 22.70 9 266.2 0.3043 4.259 19.02 8.517 9.510 34.07 2.378 3.172 25.54 Conversion of Masses Grains to grams Grams to grains Ounces (avoir.) to grams Grams to ounces (avoir.) Pounds (avoir.) to kilo- grams Kilo- grams to pounds (avoir.) Short tons (2000 Ib.) to metric tons Metric tons (1000 kg.) to short tons Long tons (2240 Ib.) to metric tons Metric tons to long tons 1 0.06480 15.43 28.35 0.03527 0.4536 2.205 0.907 1.102 1.016 0.984 2 0.1296 30.86 56.70 0.07055 0.9072 4.409 1.814 2.205 2.032 1.968 3 0.1944 46.30 85.05 0.1058 1.361 6.614 2.722 3.307 3.048 2.953 4 0.2592 61.73 113.40 0.1411 1.814 8.818 3.629 4.409 4.064 3.937 5 0.3240 77.16 141.75 0.1764 2.268 11.02 4.536 5.512 5.080 4.921 6 0.3888 92.59 170.10 0.2116 2.722 13.23 5.443 6.614 6.096 5.905 7 0.4536 108,03 198.45 0.2469 3.175 15.43 6.350 7.716 7.112 6.889 8 0.5184 123.46 226.80 0.2822 3.629 17.64 7.257 8.818 8.128 7.874 9 0.5832 138.89 255.15 0.3175 4.082 19.84 8.165 9.921 9.144 8.857 78 WEIGHTS AND MEASURES Velocity Equivalents (For conversion table see p. 80) Centimeters per sec. Meters per sec. Meters per min. Kilo- meters per hour Feet per sec. Feet per min. Miles per hour Knots 1 0.01 0.6 1.77815 0.036 2.55630 0.03281 2.51598 1.9685 0.29414 0.02237 2.34965 0.01942 2.28825 100 2.00000 1 60 1.77815 3.6 0.55630 3.281 0.51598 196.85 2.29414 2.237 0.34965 1.942 0.28825 1.667 0.22184 0.01667 2.22184 1 0.06 2.77815 0.05468 2.73783 3.281 0.51598 0.03728 2.57150 0.03237 2.51018 27.78 1.44370 0.2778 1. 44370 16.67 1.22184 1 0.9113 T. 95968 54.68 1.73783 0.6214 1.79335 0.53960 1.73207 30.48 1.48402 0.3048 F. 48402 18.29 1.26217 1.097 0.04032 1 60 1.77815 0.6818 1.83367 0.59209 1.77238 0.5080 1.70586 0.005080 3". 70586 0.3048 1.48402 0.01829 2.26217 0.01667 2.22185 1 0.01136 2.05553 0.00987 3.99423 44.70 1.65035 0.4470 r. 65035 26.82 1.42850 1.609 0.20670 1.467 0.16633 88 1.94448 1 0.86839 1.93871 51.497 1.71178 51497 F. 71178 30.898 1.48993 1.8532 0.26793 1.68894 0.22761 101.337 2.00577 1.15155 0.06128 1 Mass Equivalents (For conversion table see p. 77) Kilograms Grains Ounces Pounds Tons Troy and apoth. Avoir- dupois Troy and apoth. Avoir- dupois Short Long Metric 1 15432 4.18843 32.15 1.50719 35.27 1.54745 2.6792 0.42801 2.205 0.34333 0.0 2 1102 3.04230 0'0 3 9842 4.99309 0.001 3. 00000 0.046480 5.81157 1 0.0 2 2083 3.31876 0.0 2 2286 3.35902 0.0 3 1736 4.23958 0.0 3 1429 4.15490 0.0 7 7143 "8. 85387 0.0 7 6378 8.80465 0.0:6480 8.81157 0.03110 2.49281 480 2.68124 1 1.09714 0.04026 0.08333 2.92082 0.06857 2.83614 0.0 4 3429 5.53511 0.0 4 3061 5.48590 0.043110 "5.49281 0.02835 2.45255 437.5 2.64098 0.9115 1.95974 1 0.07595 2.88056 0.0625 2.79588 0.0 4 3125 5.49485 0.042790 5.44563 0.0 4 2835 T. 45255 0.3732 T.57199 5760 3.76042 12 1.07918 13.17 1.11944 1 0.8229 1.91532 8.0*41 H 4.61429 0.0s3673 4.56508 0.0 3 3732 4.57199 0.4536 T. 65667 7000 3.84510 14.58 1.16386 16 1.20412 1.215 0.08468 1 0.0005 T. 69897 0.0 3 4464 4.64975 0.0 3 4536 4.65667 907.2 2.95770 140e 7.14613 29167 4.46489 320 3 4.50515 2431 3.38571 2000 3.30103 1 0.8929 T. 95078 0.9072 1.95770 1016 3.00691 15680 4 7.19535 326s 4.51411 35840 4.55437 2722 3.43492 2240 3.35025 1.12 0.04922 1 1.016 0.00691 1000 3.00000 15432356 7.18843 32151 4.50719 35274 4.54745 2679 3.42801 2205 3.34333 1.102 0.04230 0.9842 1.99309 1 The equivalents are given in the heavier type. Logarithms of the equivalents are given immediately below. Subscripts after any figure, Os, 4, -etc., mean that that figure is to be repeated the indicated number of times. CONVERSION TABLES 79 Pressure Equivalents (For conversion table see p. 80) Megabars or megadynes per sq. cm. Kilo- grams per sq. cm. (Metric atmos- pheres) Pounds per sq. in." Short tons per sq. ft. Atmos- pheres Columns of mercury at temperature 0C. Columns of water at temperature 15 C. Meters Inches Meters Inches Feet 1 1.0197 14.50 1.044 0.9S69 0.7500 29.53 10.21 401.8 33.48 0.00848 1.16148 0.01882 1.99427 1.87508 1.47025 1.00886 2.60402 1.52484 0.9807 1 14.22 1.024 0.9678 0.7355 28.96 10.01 394.0 32.84 1.99152 1.15300 0.01034 1.98579 1.86660 1.46177 1.00038 2.59555 1.51636 0.06895 - 0.07031 1 0.072 0.06804 0.05171 2.036 0.7037 27.70 2.309 2.83852 2.84700 2". 85733 2.83279 2.71360 0.30876 f. 84738 1.44254 0.36336 0.9576 0.9765 13.89 1 0.9450 0.7182 28.28 9.773 384.8 32.06 ,1.98119 1. 98966 1.14267 1.97545 1.85627 1.45143 0.99004 2.58521 1.50603 1.0133 1.0333 14.70 1.058 1 0.76 29.92 10.34 407.2 33.93 0.00573 0.01421 1.16722 0.02955 1.88081 1.47598 1.01459 2.60976 1.53058 1.3333 1.3596 19.34 1.392 1.316 1 39.37 13.61 535.7 44.64 0.12492 0.13340 1.28640 0.14373 0.11919 1.59517 1.13378 2.72894 1.64976 0.03386 0.03453 0.4912 0.03536 0.03342 0.02540 1 0.3456 13.61 1.134 2". 52975 2.53823 T. 69124 2.54857 2.52402 2.40484 1.53861 1.13378 0.05460 0.09798 0.09991 1.421 0.1023 0.09670 0.07349 2.893 | 39.37 3.281 2~.99114 2". 99962 0.15262 F. 00996 2.98541 2.86622 0.46139 1.59517 0.55198 0.002489 002538 0.03610 0.002599 0.002456 0.001867 0.07349 0.02540 1 0.08333 3.39598 3.40446 2.55746 3.41479 3.39024 3.27106 2.86622 2~.40484 2.92082 0.02986 0.03045 0.4332 0.03119 0.02947 0.02240 0.8819 0.3048 12 1 2.47516 2.48364 1.63664 2.49397 2.46942 2.35024 1.94540 1.48402 1.07918 Energy or Work Equivalents (For conversion table see p. 80) Joules = 10' ergs Kilogram- meters Foot- pounds Kilo- watt- hours Cheval- vapeur- hours Horse- power- hours Liter- atmos- pheres Kilo- gram- calories British thermal units 1 0.10197 1.00848 0.7376 1.86780 0.0e2778 7.44370 0.0o3777 7.57711 0.0 6 3725 7.57113 0.009869 3.99427 0.02390 T. 37848 0.0 3 9486 4.97709 9.80665 0.9915207 1 7.233 0.85932 0.0 5 2724 6.43522 0.0 8 37037 6.56863 0.053653 6.56265 0.09678 2.98579 0.002344 3.37000 009302 3.96861 1.356 0.13220 0.1383 1.14068 1 0.0 6 3766 7.57590 0.0 6 51206 7.70932 0.0 6 50505 7.70333 0.01338 2.12647 0.0 3 3241 4.51068 0.001286 3.10929 3.6X10 6.55630 3.671X105 5.56478 2.655X10" 6.42410 '" 1.3596 0.13342 1.341 0.12743 35528 4.55057 860.5 2.93478 3415 3.53339 2.648X10 6.42288 270000. 5.43136 1.9529X10* 6.29068 0.7355 1.86658 1 0.9863 1.99401 26131. 4.41715 632.9 2.80135 2512 3.39996 2.6845X10 8 6.42887 2. 7375X105 5.43735 1.98X10 6.29667 0.7457 1.87257 1.0139 0.00598 1 26494 4.42314 641.7 2.80735 2547 3.40595 101.33 2.00573 10.333 1.01421 ' 74.73 1.87353 0.042815 5.44943 0.0 4 3827 5.58284 0.0 4 3774 5.57686 1 0.02422 2.38425 0.09612 2.98281 4183 3.62153 426.6 2.63000 3086 3.48932 0.001162 3.06522 0.001580 3.19864 0.001558 3.19265 41.29 1.61579 1 3.968 0.59861 1054 3.02291 107.5 2.03139 777.52 2.89071 0.0 3 2928 4.46661 0.0 3 3981 4.60003 0.0 3 3927 4.59405 10.40 1.01719 0.25200 1.40139 1 The equivalents are given in the heavier type. Logarithms of the equivalents are given immediately below. Subscripts after any figure, Oi, 94, etc., mean that that figure is to be repeated the indicated number of times. V 80 WEIGHTS AND MEASURES Linear and Angular Velocity Conversion Factors Cm. per sec. to feet per min. Feet per min. to cm. per sec. Cm. per sec. to miles per hour Miles per hour to cm. per sec. Feet per sec. to miles per hour Miles per hour to feet per sec. Radians per sec. to rev. per min. Rev. per min. to radians per sec. 1 2 3 4 5 6 7 8 9 1.97 3.94 5.91 7.87 9.84 11.81 13.78 15.75 17.72 0.508 1.016 1.524 2.032 2.540 3.048 3.556 4.064 4.572 0.0224 0.0447 0.0671 0.0895 0.1118 0.1342 0.1566 0.1789 0.2013 44.7 89.4 134.1 178.8 223.5 268.2 312.9 357.6 402.3 0.682 1.364 2.046 2.727 3.409 4.091 4.773 5.455 6.136 1.47 2.93 4.40 5.87 7.33 8.80 10.27 11.73 13.20 9.55 19.10 28.65 38.20 47.75 57.30 66.85 76.39 85.94 0.1047 0.2094 0.3142 0.4189 0.5236 0.6283 0.7330 0.8378 0.9425 Conversion of Pressures Pounds per sq. in. to kilograms per sq. cm. Kilograms per sq. cm. to pounds per sq. in. Atmospheres to pounds per sq. in. Pounds per sq. in. to atmospheres Atmospheres to kilograms per sq. cm. Kilograms per sq. cm. to atmos- pheres 1 0.0703 14.22 14.70 0.0680 1.033 0.9678 2 0.1406 28.45 29.39 0.1361 2.067 1.936 3 0.2109 42.67 44.09 0.2041 3.100 2.903 4 0.2812 56.89 58.79 0.2722 4.133 3.871 5 0.3515 71.12 73.48 0.3402 5.166 4.839 6 4218 85.34 88.18 0.4082 6.200 5.807 7 0.4922 99.56 102.9 0.4763 7.233 6.774 8 0.5624 113.8 117.6 0.5443 8.266 7.742 9 0.6328 128.0 132.3 0.6124 9.300 8.710 Conversion of Energy, Work, Heat Ft.-lb. to kilo- gram- meters Kilo- gram- meters to ft.-lb. Ft.-lb. to B.t.u. B.t.u. to ft.-lb. Kilo- gram- meters to large calories Large calories to kilo- gram- meters Joules to small calories Small calories to j oules 1 0.1383 7.233 0.001286 777.5 0.002344 426.6 0.2390 4.183 2 0.2765 14.47 0.002572 1555.0 0.004688 853.2 0.4780 8.367 3 0.4148 21.70 003858 2333.0 0007033 1280.0 0'.7170 12.55 4 0.5530 28.93 0.005144 3110.0 0.009377 1706.0 0.9560 16.73 5 0.6913 36.16 0.006431 3888.0 0.01172 2133.0 1.195 20.92 6 0.8295 43.40 0007717 4665.0 0.01407 2560.0 1.434 25.10 7 0.9678 50.63 0009003 5443.0 0.01641 2986.0 1.673 29.28 8 1.106 57.86 01029 6220.0 0.01875 3413.0 1.912 33.47 9 1.244 65.10 0.01157 6998.0 0.02110 3839.0 2.151 37.65 Conversion of Power Horse powers to kilowatts Kilowatts to horse powers Metric horse powers to kilowatts Kilowatts to metric horse powers Horse powers to metric horse powers Metric horse powers to horse powers 1 0.7457 1.341 0.7354 1.360 1.014 0.9863 2 1.491 2.682 1.471 2.719 2.028 1.973 3 2.237 4.023 2.206 4.079 3.042 2.959 4 2.983 5.364 2.942 5.439 4.056 3.945 5 3.728 6.705 3.677 6.799 5.069 4.932 6 4.474 8.046 4.413 8.158 6.083 5.918 7 5.220 9.387 5.148 9.518 7.097 6.904 8 5.965 10.73 5.884 10.88 8.111 7.890 9 6.710 12.07 6.619 12.24 9.125 8.877 CONVERSION TABLES 81 Power Equivalents (For conversion table see p. 80) Horse power Kilo- watts (1000 joules per sec.) Cheval- vapeur (metric h.p.) Ponce- lets M.-kg. per sec. Ft.-lb. per sec. Kg- cal. per sec. B.t.u per sec. 550 stand- ard ft.-lb. per sec. 1 0.7457 1.014 0.7604 76.04 550 0.1783 0.7074 1.87256 0.00599 1.88105 1.88105 2.74036 1.25104 1.84965 1.341 1 1.360 1.020 102.0 737.6 0.2390 0.9486 0.12743 0.13343 0.00848 2.00848 2.86780 1.37848 1.97709 0.9863 0.7355 1 0.75 75 542.3 0.1758 0.6977 T. 99402 T. 86659 1.87506 1.87506 2.73438 1.24506 1.84367 1.315 0.9807 1.333 1 100 723.3 0.2344 0.9303 0.11896 1.99152 0.12493 2.00000 2.85932 1.37000 1.96861 0.01315 0.009807 0.01333 0.01 1 7.233 0.002344 0.009303 2.11896 3.99152 2.12493 T. 00000 0.85932 3.37000 2.96861 0.00182 0.001356 0.00184 0.00138 0.1383 1 0.0 3 3241 0.001286 3.25946 3.13219 3.26562 3.14067 T. 14067 T. 51068 T. 10929 5.610 4.183 5.688 4.266 426.6 3086 1 3.968 0.74896 0.62153 0.75494 0.63000 2.63000 3.48932 0.59861 1.414 1.054 1.433 1.075 107.5 777.5 0.2520 1 0.15035 0.02291 0.15632 0.03139 2.03139 2.89071 1.40138 The equivalents are given in the heavier type. Logarithms of the equivalents are given immediately below. Subscripts after any figure, Os, 94, etc., mean that that figure is to be repeated the indicated number of times. Density Equivalents and Conversion Factors Equivalents Conversion factors Grams per cu. cm. Lb. per cu. in. Lb. per cu. ft. Short tons (2000 lb.) per cu. yd. Lb. per U. S. gal. Grams per cu. cm. to lb. per cu. ft. Lb. per cu. ft. to grams per cu. cm. Grams per cu. cm. to short tons per cu. yd. Short tons per cu. yd. to grams per cu. cm. 1 0.03613 62.43 0.8428 8.345 1 62.43 0.01602 0.8428 1.186 2.55787 1.79539 1.92572 0.92143 2 124.90 0.03204 1.6860 2.373 27.68 1 1728 23.33 231 3 187.30 0.04806 2.5280 3.600 1.44217 3.23754 1.36792 2.36361 4 249.70 0.06407 3.3710 4.746 0.01602 0.0 3 5787 1 0.0135 0.1337 5 312.40 0.08009 4.2140 5.933 2.20466 4.76245 2.13033 1.12613 6 374.60 0.09611 5.0570 7.119 1.186 0.04286 74.07 1 9.902 7 437.00 0.11210 5.9000 8.306 0.07428 2.63205 1.86964 0.99572 8 499.40 0.12820 6.7420 9.492 0.1198 0.004329 7.481 0.1010 1 9 561.90 0.14420 7.5850 10.680 1.07855 3.63639 0.87396 1.00432 10 624.30 0.16020 8.4280 11.870 82 WEIGHTS AND MEASURES Conversion of Heat Transmission and Conduction Small B.t.u. Small B.t.u. Small calories per B.t.u. per hr. per calories per sq. calories per sq. ft. sec. per sq. cm. sq. ft. per 1 deg. per sq. cm. to ft. to small per sq. cm. per cm. to per in. to small per 1 aeg. cent, per cm. thick, to B.t.u. fahr. per in. thick to small calories B.t.u. calories B.t.u. per calories per per hr. per sq. ft. per sec. per sq. cm. P 1t s q . per sq. cm. sq. ft. per in. sq. cm. per cm. per 1 deg. fahr. per in. thick per 1 deg. cent, per cm. thick 1 3.687 0.2712 1.451 0.6892 2.903X103 0.0 3 3445 2 7.374 0.5424 2.902 1.378 5.806X103 0.0 3 6890 3 11.06 0.8136 4.353 2.068 8.709X103 0.0 2 I034 4 14.75 1.085 5.804 2.757 11.61 X1Q3 0.0 2 I378 5 18.44 1.356 7.255 3.446 14.52 X10 0.0 2 1722 6 22.12 1.627 8.706 4.135 17.42 X1Q3 0.0 2 2067 7 25.81 1.898 10.16 4.824 20.32 X1Q3 0.0 2 2412 8 29.50 2.170 11.61 5.514 23.22 X103 0.0 2 2756 9 33.18 2.441 13.06 6.203 26.13 XlO 3 0.0 2 3100 NOTE. 1 gram-calorie per sq. cm. = 3.687 B.t.u. per sq. ft. 1 gram-calorie per sq. cm. per cm. = 1.451 B.t.u. per sq. ft. per in. 1 gram-calorie per sec. per sq. cm. for a temp. grad. of 1 deg. cent, per cm. = 360 kilogram-calories per hour per sq. m. for a temp. grad. of 1 deg. cent, per m. = 2.903 X 10 3 B.t.u. per hour per sq. ft. for a temp. grad. of 1 deg. fahr. per in. Values of Foreign Coins (Legal standards: (G) = gold; (S) = silver) Country Monetary unit Value in terms of U. S. money Country Monetary unit Value in terms of U. S. money Argentina (G) Austria-Hungary (GO Belgium (G and Si aa Specific gravity Degrees Baumfi Specific gravity Degrees Baum6 Specific gravity 10 1.0000 25 0.9032 40 0.8235 55 0.7568 70 0.7000 85 0.6512 11 0.9929 26 0.8974 41 0.8187 56 0.7527 71 0.6965 86 0.6482 12 0.9859 27 0.8917 42 0.8140 57 0.7487 72 0.6931 87 0.6452 13 0.9790 28 0.8861 43 0.8092 58 0.7447 73 0.6897 88 0.6422 14 0.9722 29 0.8805 44 8046 59 0.7407 74 0.6863 89 0.6393 15 0.9655 30 0.8750 45 0.8000 60 0.7368 75 0.6829 90 0.6364 16 0.9589 31 0.8696 46 0.7955 61 0.7330 76 0.6796 91 0.6335 17 0.9524 32 0.8642 47 0.7910 62 0.7292 77 0.6763 92 0.6306 18 0.9459 33 0.8589 48 0.7865 63 0.7254 78 0.6731 93 0.6278 19 0.9396 34 0.8537 49 0.7821 64 0.7216 79 0.6699 94 0.6250 20 0.9333 " 35 0.8485 50 0.7778 65 0.7179 80 0.6667 95 0.6222 21 0.9272 36 0.8434 51 0.7735 66 0.7143 81 0.6635 96 0.6195 22 0.9211 37 0.8383 52 0.7692 67 0.7107 82 0.6604 97 0.6167 23 0.9150 38 0.8333 53 0.7650 68 0.7071 83 0.6573 98 0.6140 24 0.9091 39 0.8284 54 0.7609 69 0.7035 84 0.6542 99 0.6114 100 0.6087 60 Specific Gravities at Pahr. Corresponding to Degrees Baume for Liquids Heavier than Water Calculated from the formula, specific gravity fahr. = Degrees Baum6 Specific gravity Degrees Baume Specific gravity Degrees Baum6 >> 11 02 00 ii Specific gravity Degrees Baume 1 Degrees Baume Specific gravity .0000 12 .0902 24 .1983 36 .3303 48 .4948 60 .7059 1 .0069 13 .0985 25 .2083 37 .3426 49 .5104 61 .7262 2 .0140 14 .1069 26 .2185 38 .3551 50 .5263 62 .7470 3 .0211 15 .1154 27 .2288 39 .3679 51 .5426 63 .7683 4 .0284 16 .1240 28 .2393 40 .3810 52 .5591 64 .7901 5 .0357 17 .1328 29 .2500 41 .3942 53 .5761 65 .8125 6 .0432 18 .1417 30 .2609 42 .4078 54 .5934 66 .8354 7 .0507 19 .1508 31 .2719 43 .4216 55 .6111 67 .8590 8 .0584 20 .1600 32 .2832 44 .4356 56 .6292 ^68 .8831 9 .0662 21 .1694 33 .2946 45 .4500 57 .6477 69 .9079 10 .0741 22 .1789 34 .3063 46 .4646 58 .6667 70 .9333 11 .0821 23 .1885 35 .3182 47 .4796 59 .6860 Mohs's Scale of Hardness 1. Talc. 2. Gypsum. 3. Calc spar. 4. Fluorspar. 5. Apatite. 6. Feldspar. 7. Quartz. 8. Topaz. 9. Sapphire. 10. Diamond. SECTION 2 MATHEMATICS BY EDWARD V. HUNTINGTON, Ph. D. ASSOCIATE PROFESSOR OF MATHEMATICS, HARVARD UNIVERSITY, FELLOW AM. ACAD. ARTS AND SCIENCES CONTENTS ARITHMETIC PAGE Numerical Computation 88 Logarithms 91 The Slide Rule 94 Computing Machines 97 Financial Arithmetic 98 GEOMETRY AND MENSURATION Geometrical Theorems 99 Geometrical Constructions 101 Lengths and Areas of Plane Figures. 105 Surfaces and Volumes of Solids 107 ALGEBRA Formal Algebra 112 Solution of Equations in One Un- known Quantity 116 Solution of Simultaneous Equations 119 Determinants 123 Imaginary or Complex Quantities 124 TRIGONOMETRY Formal Trigonometry 128 Solution of Plane Triangles 132 Solution of Spherical Triangles 134 Hyperbolic Functions 135 ANALYTICAL GEOMETRY The Point and the Straight Line. ... 136 The Circle 137 PAOE The Parabola 138 The Ellipse 140 The Hyperbola 144 The Catenary 147 Other Useful Curves 151 DIFFERENTIAL AND INTEGRAL CALCULUS Derivatives and Differentials 1 57 Maxima and Minima 159 Expansion in Series 160 Indeterminate Forms 163 Curvature 163 Table of Indefinite Integrals 164 Definite Integrals 169 Differential Equations 171 GRAPHICAL REPRESENTATION OF FUNCTIONS 173 174 176 177 178 182 Equations Involving Two Variables Equations for Empirical Curves . Logarithmic Cross-section Paper . Semi-logarithmic Paper Equations Involving Three Variables Equations Involving Four Variables VECTOR ANALYSIS Vector Analysis 185 COPYRIGHT, 1916, BY EDWARD V. HUNTINGTON MATHEMATICS BY EDWARD V. HUNTINGTON ARITHMETIC NUMERICAL COMPUTATION Number of Significant Figures. In any engineering computation, the data are ordinarily the results of measurement, and are correct o'nly to a limited number of significant figures. Each of the numbers 3.840 and 0.003840 is said to be given "correct to four figures;" the true' value lies in the first case between 3.8395 and 3.8405; in the second case, between 0.0038395 and 0.0038405. The absolute error is less than 0.001 in the first case, and less than 0.000001 in the second; but the relative error is the same in both cases, namely, an error of less than "one part in 3840." If a number is written as 384000, the reader is left in doubt whether the number of correct significant figures is 3, 4, 5, or 6. This doubt can be removed by writing the number as 3.84 X 10 or 3.840 X 10 s or 3.8400 X 10* or 3.84000 X 10 5 . In any numerical computation, the possible or desirable degree of accuracy should be decided on and the computation should then be so arranged that the required number of significant figures, and no more, is secured. Carry- ing out the work to a larger number of places than is justified by the data, is to be avoided, (1) because the form of the results leads to an erroneous impres- sion of their accuracy, and (2) because time and labor are wasted in super- fluous computation. The labor of working with six-place tables is nearly three times as great as that with four-place tables. In computations involv- ing several steps, it is desirable to retain one extra figure until just before the final result is reached, in order to protect the last figure against the possible cumulative effect of small tabular errors. In discarding superfluous figures, if the first discarded figure is 5 or more, increase the preceding figure by 1. Thus, 3.14159, written 'correct to four figures, is 3.142; correct to three figures, 3.14. Again, 6.1297, correct to four figures, is 6.130. Addition. In adding numbers, note that a doubtful final . 2056x figure in any one number will render doubtful the whole col- 2 . 572xx umn in which that figure lies; hence all figures to the right of 14.25xxx that column are superfluous, and contribute nothing to the 576.1xxxx accuracy of the result. Subtraction. The "Austrian" or "shop" method is 593.1 recommended. The mental process is as follows, the figures here printed in boldface type being the only ones written down: [3 plus how many is 12?] 3 plus 9 is 12; 1 to carry. 14752 [7 plus how many is 15?] 7 plus 8 is 15; 1 to carry. ,J^5, 5 plus 2 is 7. 8 plus 6 is 14. 6289 88 NUMERICAL COMPUTATION 89 This method is especially useful when it is desired to subtract from a given number the sum of several other numbers. 7 plus 1 is 8; plus 5 is 13; plus 9 is 22; 2 to carry. 14752 5 plus is 5; plus 2 is 7; plus 8 is 15; 1 to carry. 3125~| 3 plus 1 is 4; plus 1 is 5; plus 2 is 7. 101 5 plus 3 is 8; plus 6 is 14. _5237-J 6289 The use of a wavy line to indicate subtraction is also recommended, as it will minimize the danger of adding when subtraction is intended. Multiplication. In long examples in multiplication, 4956 the arrangement of work here illustrated is recommended, 8372 since it facilitates the abbreviation of the work by the 39648 omission, in practice, of all the figures on the right of the 1486 8 vertical line. 346 92 The position of the decimal point should be determined 9 912 by reference'to the first, or left-hand, figures of the numbers, 41492|xxx rather than by "pointing off" so-and-so many places from the right-hand end. For the right-hand figures of a number are the least important ones, and in many cases are entirely unknown (especially when the slide rule or a computing machine is used). The mental process for determining the decimal point is as follows: (a) If the multiplier is a number like 3.1416, with only one figure preceding the decimal point, think of this number as "a little over 3;" then the product must be "a little over three times the number which is being multiplied;" and this gives the position of the decimal point at once, by inspection. (6) If the multiplier is a number like 3141.6 [or 0.000 003 141 6], think of this number as "about 3, with the point moved three places to the right" [or "about 3, with the point moved six places to the left"]; then think what the answer would be if the multiplier were simply "about 3," and shift the decimal point accordingly. Multiplication Tables. Crelle's large volume (Berlin, G. Reimer) gives the product of every three-figure number by every three-figure number; Peters's (Berlin, G. Reimer), of every four-figure number by every two-figure number. The smaller table of H. Zimmermann (Berlin, Wm. Ernst) gives the product of every three-figure number by every two-figure number. Division. In long division, where the numbers are given 23026)31416(1 only approximately, the work can be much abbreviated with- 23026 out loss of accuracy by "cutting off" one figure of the divisor 2303) 8390(3 at each step, instead of "bringing down" a doubtful zero in 6909 the dividend. Thus, 3.1416 4- 2.3026 = 1.3644. To determine the position of the decimal point in a du; problem of fractional division, shift the point (mentally) in both numerator and denominator (the same number of 23) 101(4 places in each) until the denominator is a number in the "standard form, " that is, a number with only one figure pre- 2) 9(4 ceding the decimal point. (This will not change the value of the fraction.) Then estimate the approximate magnitude of the quotient by inspection. Thus: 0.2718 0.000 2718 "about 0.000 09" = 0.000 08652; 3141.6 3.1416 31.416 31 416. 0.002718 2.718 "about 10 000" =11 558. 90 ARITHMETIC Reciprocals. The reciprocal of N is 1 /N. Instead of dividing by a long number N, it is often better to multiply by the reciprocal of N. The table of reciprocals on pp. 24-27 gives the reciprocal of any number, correct to four figures. Barlow's Table (Spoil & Chamberlain, New York) gives the reciprocal of every four-figure number correct to seven figures (but with- out facilities for interpolation). The reciprocals of numbers having more than four figures are best found by the use of a large table of logarithms. Reciprocals of I + x when x is Small. 1/(1 + x) = 1 - x + [error < x 2 , if x is between and 1], = 1 x + x z [error < x 3 , if x is between and 1]. 1/(1 x) = 1 + x + [error < x 2 + 2z 3 , if x is between and }*], = 1 + x + x 2 + [error < x 3 + 2z 4 , if x is between and #]. NOTE. l/(o 6) = (l/a)[l/(l )], where x = 6/a. Notation by Powers of 10. All questions concerning the position of the decimal point are readily answered if each number is expressed in the "stand- ard form," that is, as the product of two factors, one of which is a number with only one figure preceding the decimal point, while the other is a positive or negative power of 10. Thus, 3.1416 X 10 3 means 3.1416 with the point moved three places to the right, that is, 3141.6. Again, 3.1416 X 10~ 6 means 3.1416 with the point moved six places to the left, that is, 0.000 003 1416. This notation by powers of 10 should always be used in dealing with very large or very small numbers. Among electrical engineers its use is very general, even for numbers of moderate size. Square Root, (a) If four figures of the root are sufficient, take the answer directly from the table of square roots, pp. 12-15. (6) To obtain a root of six or seven figures from the table, use the formula: VJV = a + [(N ,a 2 )/2a] (approx.), where a is the nearest value of v~N obtainable from the table, with three or four ciphers annexed. Here a 2 must be found exactly, by direct multiplication, so that at least three significant figures of the difference N a 2 shall be known correctly; but this done, the division of N a 2 by 2a should be carried to only three figures (logarithms or slide rule may be used). NOTE. The simplest way to obtain any root of a seven-figure number correct to seven figures is to use a seven-place table of logarithms, if such a table is at hand. Square Roots of 1 x when x is Small. (1 + *)** = 1 + \hx - [error less than ftx 2 if < x < 1] = 1 + Kx - Hx z + [error < H * 3 if < x < 1] (1 - x) W = 1 - MX - [error < #c a + Mo* 3 if < x < J4] = 1 - )6x - ^z 2 -[error < Ho* 3 + Hex 4 if < x < ft] NOTE. Va + b = Va (1 + x)^ t where x = 6/a. Cube Root, (a) If four figures of the root are sufficient, take the answer directly from the table of cube roots, pp. 16-21. (6) To obtain a root of six or seven figures from the table, use the formula: %/N = a + [(N o 3 )/3a 2 ] (approx.), where a is the nearest value of $/N obtainable from the table, with three or four ciphers annexed. Here a 3 must be found correct to seven or eight figures, by direct multiplication, so that at least three significant figures of the difference N a 3 shall be known; but this done, the division of N a 8 by 3o 2 should be carried to only three or four figures (logarithms or the slide rule may be used). LOGARITHMS 91 NOTE. The simplest way to obtain any root of a seven-figure number correct to seven figures is to use a seven-place table of logarithms, if such a table is at hand. Cube Roots of 1+x when x is Small. (1 + z) H = 1 + MX - [error < H* 2 if < a: < 1], = 1 + %x - Kx* + [error < Me* 3 if < * < 1], (1 - x) % = 1 - %x - [error < %x* + Mo* 3 if < x < H], = 1 - MX -Jte 2 - [error < Me* 3 + Ms* 4 if < x < ft]. NOTE. 3/a + 6 = ^/a(l + z)**, where x = b/a. LOGARITHMS Tables of Logarithms. The use of a table of logarithms greatly reduces the labor of multiplication, division, raising to powers, and extracting roots. The table on pp. 42-43 is carried out to four significant figures, and the follow- ing explanations should be sufficient to permit the use of the table readily, even by one without previous experience. For algebraic theory, see p. 113. If more than four-figure accuracy is required, recourse must be had to a larger table. Five-place tables are available in great variety; the Macmillan Tables, 1913, are perhaps as convenient as any. If more than five figures are required, use Bremiker's six-place table, or proceed at once to a seven-place table: Schron (Vieweg und Sohn, Braun- schweig); Bruhns; Vega-Bremiker. If extreme accuracy is required, use the eight-place* table by Bauschinger and Peters (Engelmann, Leipzig). Logarithmic paper, see p. 176. To Find the Logarithm of Any Given (Positive) Number. (a) WHEN THE GIVEN NUMBER is BETWEEN 1 AND 10. An inspection of the table on pp. 42-43 shows that as the number increases from 1 to 9.99. . . the logarithm of that number increases continuously from to 0.999. . . For example, log 2.97 = 0.4728; log 2.98 = 0.4742. If the given number contains four significant figures, it is necessary to inter- polate between the tabulated values, as follows: To find log 2.973, notice that this number is fio of the way from 2.97 to 2.98; hence its logarithm will be (approximately) Mo of the way from 0.4728 to 0.4742. The difference here is 14 units, and iHo of this difference is 4 (to the nearest unit); hence, by adding this 4 to 4728, log 2.973 = 0.4732. This process of interpolating should be performed mentally; the step of finding the tabular difference will be facilitated by a glance at the last column on the right, which gives, for each line of the table, the average of the differences along that line. Again, to find log 4.098: From table, log 4.09 = 0.6117; adding 9io of the difference (11), or about 9, gives: log 4.098 = 0.6126. Or better, since 91o f the way forward is equal to Y\Q of the way back, find in table log 4.10 = 0.6128, and subtract Y\Q of 11, or 2, giving log. 4.098 = 0.6126. It should be noted that any interpolated value may be in error by 1 in the last place. If the given number contains more than four significant figures, it should be cut down to four figures (see p. 88), since the later figures will not affect the result in four-place computations. (6) WHEN THE GIVEN NUMBER is LESS THAN 1 OR MORE THAN 10, it is simply necessary to notice that every such number can be regarded as obtainable from some number between 1 and 10 by merely shifting the decimal point (see p. 90) ; and that according to the rule at the foot of the table, moving the decimal point n places to the right [or left] in the number-column is equivalent to adding n [or n] to the logarithm in the body of the table. For example, to find log 2973. Here 2973 = 2.973 X 10 (i.e., 2.973 with the decimal point moved 3 places to the right). From the table, log 2.973 => 0.473i. Hence, log 2973 = 0.4732 + 3, which may be written as 3.4732. 92 ARITHMETIC Again, to find log 0.0002973. Here 0.0002973 = 2.973 X 10~* (i.e., 2.973 with the decimal point moved 4 places to the left). From the table, log 2.973 = 0.4732. Hence, log 0.0002973 = 0.4732 - 4. (This may be written as 4.4732, if desired, and is equal of course, to _ 3.5268; this latter form, however, is not convenient in practice.) It is thus evident that the logarithm of every positive number may be regarded as consisting of two parts: a decimal fraction, which is always posi- tive (or zero) ; and a whole number, which may be positive, negative, or zero. The fractional part is called the mantissa, and is found from the table ; the whole-number part is called the characteristic, and is determined by inspection. To Find the Number Corresponding to a Given Logarithm. (a) WHEN THE GIVEN LOGARITHM is A POSITIVE DECIMAL FRACTION (CHARAC- TERISTIC ZERO), simply reverse the process for finding the logarithm of a number between 1 and 10. For example, given log N = 0.4732; to find N. In the body of the table it is seen that 0.4732 lies a little beyond 0.4728; hence N must lie a little beyond 2.97. By taking differences it is found that 4728 is in fact #4 of the way from 0.4728 to the next higher logarithm; therefore N must be y\ of the way from 2.97 to the next higher number. But YU of 1 is 0.3 (to the nearest tenth), hence N = 2.973. Again, given log N = 0.6126; to find N. Here, 0.6126 is %i of the way from 0.6117 to the next higher logarithm; therefore N must be JH \ of the way from 4.09 to the next higher number. But %\ of 1 is 0.8 (to the nearest tenth), hence N = 4.098. (6) WHEN THE GIVEN LOGARITHM HAS ANY GIVEN VALUE (CHARACTERISTIC NOT ZERO), proceed as follows: First, be sure the given logarithm is in the "standard form," that is, a positive decimal fraction (mantissa) plus a posi- tive or negative whole number (characteristic). For example, if log N is originally given in the form log N = 3.5268, tfiis must first be reduced to the (equivalent) form log N = 0.4732 4 (or 4.4732), before entering the table. Having the logarithm given in the standard form, suppose for the moment that the characteristic is zero, and find in the table the number corresponding to the given mantissa; then move the decimal point to the right or left according as the value of the characteristic is positive or negative. For example, given log N = 0.4732 + 3; to find N. From the table, the number corresponding to 0.4732 is 2.973. The characteristic ( + 3) directs that the decimal point be moved 3 places to the right; hence N = 2.973 X 10 3 = 2973. Again, given log N = 0.4732 4; to find N. From the table, the number corre- sponding to 0.4732 is 2.973. The characteristic ( - 4) indicates that the decimal point is to be moved 4 places to the left; hence N = 2.973 X 10~ = 0.0002973. The number corresponding to a given logarithm is called its antiloga- rithm. Thus, if log 2973 = 0.4732 + 3, then 2973 = antilog (0.4732 + 3). NOTE 1. In most tables of logarithms the decimal point is omitted, the tables being in fact not tables of logarithms, but tables of mantissas. This omission is of no con- sequence to the experienced computer, but is often perplexing to one who makes only occasional use of such tables. NOTE 2. Many computers prefer to write negative characteristics in the form of some positive number minus some multiple of 10; thus, 0.4732 4 = 6.4732 10; 0.4732 - 13 = 7.4732 - 20; etc. Fundamental Properties of Logarithms. The usefulness of logarithms in computation depends on the following properties: (1) log (a&) = log a + log 6; (3) log (a 71 ) = n log a; (2) log (a/6) = log a - log 6; (4) log \/a = (1/n) log a; (5) log 10 n = n It is to be noted also that log 1 = 0, log 10 =1, and log (1/n) = log n. LOGARITHMS 93 To Multiply by Logarithms. Find from the table the log. of each factor, and add; the result will be the log. of the product. Then find the product itself from the table. EXAMPLE". To find log 4.098 = 0.6126 x - (4.098) (0.0002973) (72.1). log 0.0002973 - 0.4732 - 4 Answer: x = 8.784 X lO"' lg 72.1 - 0.8579 -f 1 = 0.08784 log x = 1.9437 - 3 - 0.9437 - 2. To Divide by Logarithms. First Method: Find from the table the log. of the numerator and the log. of the denominator, and subtract the second from the first; the result will be the logarithm of the quotient. Then find the quotient itself from the table. 4.098 log 4.098 - 0.6126 EXAMPLE. To find x = ^^ ^ ^^ = ^732^ Answer: x - 1.378 X 10 = 13780 log x - 0.1394 -f 4 In order to avoid negative mantissas in cases where a larger mantissa would have to be subtracted from a smaller, modify the upper logarithm by adding and subtracting 1. 0.0291 log 0.0291 - 0.4639 - 2 = 1.4639 - 3 EXAMPLE. To find x = _ _ Answer: x = 4.590 X 10~ log 3 "*"- 06618^4 = 0.0004590. But if the logarithms are written with the characteristics in front, and the "shop method" of subtraction is used (see p. ] O g Q 0291 = 24639 88), then no such special device is here j og 3 4 ,_, j g021 required. Thus: T~ log x = 4.6618 To Divide by Logarithms. Second Method: Instead of subtracting the log. of a number, it is often convenient to add the cologarithm of that number; the colog. of N being defined by: colog N = log (l/N) = log N. To find the colog. of a number, write the log. of the number in the stand- ard form, and subtract it from 1.0000 1, as in the following examples: 1.0000 - 1 1.0000 - 1 log 69.5 = 0.8420 + 1 log 0.0002973 = .4732_-j4 colog 69.5 = 0.1580 - 2 colog 0.0002973 = 0.5268 + 3 This subtraction should be performed mentally. Thus, to subtract the mantissa, subtract each digit from 9 until the last non-zero digit is arrived at, and subtract this from 10; to subtract the characteristic, follow the regular rule of algebra ("reverse the sign and add"). Hence, if the logarithm itself is already written down, or can be read off from the table without interpolation, the cologarithm can be written down at once, by inspection. The use of cologarithms is not essential in logarithmic computation, but it often facilitates a compact arrangement of the work, especially in cases where the denominator of a fraction is itself the product of two or more factors. To Find the nth Power of a Number by Logarithms. Find from the table the log. of the number, and multiply it by n; the result will be the logarithm of the nth power of that number. Then find the power itself from the tables. EXAMPLE 1. Find x = (0.0291) s log 0.0291 = 0.4639 - 2 Answer: x = 2.464 X 10~ 3 = 0.00002464. log x = 1.3917 - 6 - 0.3917 - 5. 94 ARITHMETIC EXAMPLE 2. Find x = (0.0291)i'i log 0.0291 = 0.4639 - 2 = - 1.5361 Answer: x = 6.825 X 10~ 8 1.41 = 0.006825 15361~ 61444 15361 logs = - 2.1659 = 0.8341 - 3 To Find the nth Root of a Number by Logarithms. Find from the table the log. of the number, and divide it by n; the result will be the log. of the nth root of that number. Then find the root itself from the table. EXAMPLE. Find x = ^/4.098 log 4.098 = 0.6126 Answer: x = 1.600 log x = 0.2042 In order to avoid fractional characteristics, if the characteristic is not divisible by n, make it so divisible by adding and subtracting a suitable number before dividing. EXAMPLE. Find x = VO-0004590. log 0.0004590 = 0.6618 - ' Answer: x = 7.714 X 10-2 3)2.6618 - 6 = 0.07714 log x = 0^8873 - 2 But if the characteristic is positive, it is simpler to write it in front of the mantissa, and then divide directly. THE SLIDE RULE The slide rule is an indispensable aid in all problems in multiplication, division, proportion, squares, square roots, etc., in which a limited degree of accuracy is sufficient. The ordinary 10-in. Mannheim rule (see below) costs $3 to $4.50 and gives three significant figures correctly; the 20-in. rule ($12.50) gives from three to four figures; the Fuller spiral rule ($30) or the Thacher cylindrical rule ($35) gives from four to five figures. For many problems the slide rule gives results more rapidly than a table of loga- rithms; it requires, however, more care in placing the decimal point in the answer. In all work with the slide rule, the position of the decimal point should be determined by inspection (see p. 89), only the sequence of digits being obtained from the instrument itself. Rapidity in the use of the in- strument depends mainly on the skill with which the eye can estimate the values of the various divisions on the scale; expertness in this respect comes only with practice. The following explanations should be sufficient to per- mit the use of the ordinary slide rule successfully without previous experience and without knowledge of logarithms. Multiplication and Division with a (Theoretical) Complete Loga- rithmic Scale. Consider a complete logarithmic scale (D, Fig. 1), assumed to extend indefinitely in both directions, only the main section, from 1 to 10, however, being usually available. Note that the divisions within the several sections are indentical, except that the numeral attached to each divi- sion of any one section is ten times the numeral attached to the corresponding division in the preceding section. [The distances laid off from 1 are propor- tional to the logarithms of the corresponding numbers, the distance from 1 to 10 being taken as unity.] Consider also a duplicate scale, C, numbered from 1 to 10, and arranged to slide along the fixed scale D as in the figures. By means of such a scale D, and slide C, any two numbers between 1 and 10 (and hence any two numbers whatever, with proper attention to the decimal point) can be multiplied or divided, as in the following examples. THE SLIDE RULE 95 To MULTIPLY 4 BY 6. In Fig. 1, starting with point 1 of the fixed scale, run the eye along from 1 to 4; then set the 1 of the slide opposite this point 4, and run the eye forward along the slide from 1 to 6 ; the point thus reached on the fixed scale is 24, which is equal to 4 X 6. This process gives the distance from 1 to 4 plus the distance from 1 to 6, and is, in fact, a mechanical method of adding the logarithms of these numbers; hence the result is the product of the numbers. Conversely, 4 5 6 7 891 FIG. 1. To DIVIDE 4 BY 6. In Fig. 2, starting with the point 1 of the fixed scale, run the eye along from 1 to 4; then set the 6 of the slide opposite the point 4, and run the eye backward along the slide from 6 to 1 ; the point thus reached on the fixed scale is 0.667, which is equal to 4 -r- 6. This process gives the dis- tance from 1 to 4 minus the distance from 1 to 6; and is, in fact, a mechanical method of subtracting the logarithms of these numbers; hence the result is their quotient. 3 4 5 6 7 8 9 l|0 _______ 20 ____ jQ_ 40 50 60 70 l-O ____________ ^i 4 + 6 667 FIG. 2. Multiplication and Division, Using Only a Single Section of the Scale. If only the main section of scale D is available (as is usually the case in practice), the result of multiplication may fall beyond the scale, as it does in. Fig. 1. In such cases divide the first factor by 10 before beginning to multiply; this will bring the result within the scale, without affecting the sequence of digits. For example, to multiply 4 by 6. Having found that the setting shown in Fig. 1 is not successful, reset the slide as in Fig. 3, with 10 instead of 1 opposite 4; run the eye backward along the slide from 10 to 1, thus reaching the (unrecorded) point correspond- ing to 4 -j- 10; then, continuing from "this point, run the eye forward along the slide from 1 to 6, as before; the point finally reached on the main scale is 2.4, which has the Bame sequence of digits as the required value 24. After a little practice, this preliminary step of dividing by 10 will be performed almost intuitively. Whether or not this step is necessary in any given case, can be determined only by trial. The general rule for multiplication may be stated as follows, if pre- ferred: To find the product of two factors, find one factor on the fixed scale; opposite this, set (tentatively) point 1 of the slide; on the slide find the sec- ond factor, and opposite this read the product on the main scale, if possible. If the product falls beyond the scale, begin over again, using point 10 of the slide instead of point 1. In division also, the result may fall beyond the main section of the scale, as it does in Fig. 2. In such cases, it suffices merely to multiply the result by 10 in order to bring it within the scale; this will not affect the sequence of digits. 96 ARITHMETIC For example, to divide 4 by 6, set the slide as in Fig. 4, and follow out mentally the steps indicated by the arrows. It will be noticed that the supplementary step of multi- plying by 10 is performed by simply running the eye along the slide from 1 to 10 without resetting the slide; for this reason, division on the slide rule is slightly easier than multiplication. 5 6 7 6 9 l|p i 3 4 56769 l|o -*j 4(*tO)x6'U FIG. 3. FIG. 4. The Ordinary Mannheim Slide Rule has four scales, A, B, C, D, as shown in Fig. 5. Scales. C and D are essentially the same as the C and D scales described above, and the principle just explained shows how they are used in multiplication and division. The fact that the D scale covers only the main section from 1 to 10 (all decimal points being omitted) is practically no restriction on the scope of the scale, as is seen in the preceding examples. A runner is provided, so that intermediate positions reached in the course of an extended computation may be indicated temporarily on the scale without the necessity of reading off their numerical values. The best runners are those which have no side frame to obscure the numerals. f A 1 W FIG. 5. In problems involving successive multiplications and divisions, arrange the work so that multiplication and division are performed alternately. X & X c For example, to calculate -, divide the product a X & by d; multiply this dX e quotient by c; and divide this product by e. Each operation will require only one shift- ing either of the slide (for multiplication) or of the runner (for division). To multiply a number of different quantities by a constant multiplier, x, set the point 1 of slide opposite x, and read, by aid of the runner, the prod- ucts of x by all the quantities which do not fall beyond the scale; then reset the slide, setting 10 instead of 1 opposite x, and read the products of x by all the remaining quantities. To divide a number of different quantities by a constant divisor, y, first find (by the slide rule) the quotient 1 -i- y, and then use this as a constant multiplier. Scales A and B are exactly like scales C and D, except that they cover two sections of the complete logarithmic scale, the graduations being only half as fine. Either pair of scales may be used for multiplication and division; C and D give more accurate readings, but have the disadvantage that in the case of multiplication the slide must often be shifted to the other end in order to keep the result on the scale an inconvenience which is not present when the less accurate scales A and B are employed. By the use of both pairs of scales, problems in squares and square roots may be readily solved; for every number on A, except for the decimal point, is the square of the number directly below it on D (use the runner). COMPUTING MACHINES-, FINANCIAL ARITHMETIC 97 A scale of sines, tangents, and logarithms is often printed on the back of the slide. For further details concerning the use of the slide rule in various problems, see the instruction books furnished with each instrument: Wm. Cox, "Manual of the Mannheim Slide Rule;" F. A. Halsey, "Manual of the Slide Rule;" etc. Other Types of Slide Rules. The duplex slide rule ($5 to $18 according to length) shows on one face the regular A, B, C, D scales, and on the other face the scales A, B', C', D (where B' and C' are the same as B and C, only numbered in the re- verse order), with a runner encircling the whole scale. This arrangement makes possible the solution of more complicated problems with fewer settings of the slide, but if the rule is to be used only for simple problems, the multiplicity of scales is rather con- fusing. Less complicated is the polyphase rule, which is like a Mannheim rule with the addition of a single inverted scale, C", printed in the middle of the slide. The log log duplex slide rule (10 in., $8) is especially adapted for handling complex problems involving fractional powers or roots, hyperbolic logarithms, etc. A number of circular slide rules are on the market, the best of which are operated by a milled thumbnut, like the stem wind of a watch. The advantage of the circular rule, aside from its com- pact size (some models are scarcely larger than a watch), lies in the fact that the scale is endless, so that the slide never has to be reset in order to bring the result within the scale. A disadvantage is found in the necessity of reading the figures in oblique positions, or else continually turning the instrument as a whole in the hand. The Fuller and Thacher rules already mentioned are invaluable for problems requiring greater accuracy than can be obtained with the ordinary rules. There are also many special slide rules, adapted to various special types of computation, such as calculating discharge of water through pipes, horse power of engines, dimensions of lumber, stadia measurements, etc. One of the most recent devices of this kind is the Ross meridiograph (L. Ross, San Francisco, Cal.), which is a circular slide rule for solving certain cases of spherical triangles. The Eichhorn trigonometrical slide rule solves any plane triangle. COMPUTING MACHINES For certain purposes computing machines have ceased to be luxuries and have become almost necessities; but they are expensive, and should be selected with reference to the special work which is to be done. The machines may be classified roughly into three groups, as follows: Adding Machines, Non-listing. Of the machines of this kind, the most convenient in the hands of a careful operator is the well-known Comptometer (Felt & Tarrant Co., Chicago, 111.; $250 to $350 according to size), or the recent Burroughs non-listing adding machine (Detroit, Mich., $175). To add a number, simply press a key in the proper column; the result appears on the dials in front of the keyboard. Multi- plication as well as addition can be performed on this machine with great rapidity, and division also after a little practice. Weight, about 15 Ib. Much less rapid, but less expensive and requiring somewhat less skill in operation, is the Barrett adding machine (Philadelphia, Pa.) with multiplying attachment. Other key-operated machines are the Mechanical Accountant (Providence, R. I.), and the Austin (Baltimore, Md.). The American adding machine (American Can Co., Chicago, 111.; $39,50) is operated by pulling up a finger-lever for each digit. Small machines, operated by the use of a stylus, are the Rapid computer (Benton Harbor, Mich., $25); the Gem (Automatic Adding Machine Co., New York; $10), the Arithstyle (New York, $36) and the Triumph (Brooklyn, N. Y., $35). These machines, while much less rapid than the key-operated machines, are useful in simple addition. The Under- wood typewriter is now supplied with a complete electrically driven adding machine attached, and the Wahl adding attachment is supplied on the Rem- ington and other typewriters. Ray Subtracto-Adder (Richmond, Va. f $25). Adding and Listing Machines. The machines of this group not only add, but also print the items, totals and sub-totals. The Burroughs (Detroit, Mich.), the Wales (Ad- der Machine Co., Wilkes-Barre, Pa.), the Comptograph (Chicago, 111.) and the White (New Haven, Conn.), resemble each other in having an 81-key keyboard; the Dalton (Cincinnati, Ohio) and the Commercial (White Adding Machine Co., New Haven, 98 ARITHMETIC Conn.) have a 10-key and a 9-key keyboard respectively, admitting of operation by the touch method. On all these machines, in order to add a number, first depress the proper keys and then pull a handle (or, in the case of electrically driven machines, press a button) to record the item. Multiplication cannot be performed conveniently, except on the Dalton. Subtraction can be performed only by adding the complement, except on the Commercial and on one type of the Burroughs. The prices range from $125 to $600, according to size and style, new models being constantly devised for special com- mercial purposes. A new and more portable machine of the 81-key type is the Barrett adding and listing machine (Philadelphia, Pa., $250). A cheaper machine, with a 10- key keyboard, is the Standard (St. Louis, Mo.). The new American adding and listing machine (American Can Co., Chicago, 111.), operated by pulling up a finger-lever for each digit, costs only $88. The Ellis (Newark, N. J.) is an elaborate adding and listing machine having a complete typewriter incorporated with it. The Elliott-Fisher bookkeeping machine (Harrisburg, Pa.) and the Moon-Hopkins billing ma- chine (St. Louis, Mo.) are intended primarily for commercial use; the latter is a com- plicated electric machine ($750) which combines many of the features of an adding and listing machine with those of a calculating machine. Calculating Machines (so-called). Machines of this third group are intended primarily for multiplication and division; the types which have a keyboard can be used effectively for addition and subtraction also. They are all non-listing. The earliest commercially successful types were the Thomas and the Brunsviga. In both these types the multiplicand is set up by moving pegs in slots, or (in the newest models) by depressing keys, and the multiplication is effected by turning a handle for each digit of the multiplier twice for a digit 2, three times for a digit 3, etc. ; the result then appears on the dials. In the Thomas type the handle always turns in the same di- rection, the change from multiplication to division being effected by a shift key. In the Brunsviga type the handle is turned forward for multiplication and backward for divi- sion. Among the best examples of the Thomas type now on the American market are the Tim, with a single row of dials, the Unitas, with a double row of dials (both sold by Oscar Miiller Co., New York City; also with keyboard and electric drive), and the Reuter (Philadelphia, Pa.). Prices, $300 upward. Another machine of this type, with keyboard, is the Record (U. S. Adding Machine Co., New York City). The Brunsviga is represented by Carl H. Reuter, Philadelphia, Pa. ; various models. Of somewhat similar type are the Triumphator (New York City; $250), and Colt's calculator (Culmer Engineering Co., New York City). A new machine, on the same principle, but with keyboard, is the Monroe (made in Orange, N. J.; $250). The Millionaire (W. A. Morschhauser, New York City; $400), is from the mechanical point of view, the only true multiplying machine on the market (except the Moon-Hopkins). After the multiplicand is set up on the pegs, the digits of the multiplier are indicated successively by moving a pointer, the handle being turned only once for each digit. Further, the movement of the carriage is automatic. The newest models have key- board and electric drive. The Ensign electric calculating machine (Boston, Mass. ; $400) is a new machine with an 81-key keyboard on which it adds like an adding machine, and a secondary 10-key keyboard by means of which it multiplies and divides quite as rapidly as any of the calculating machines, the proper key being pressed just once for each digit of the multiplier. The National calculator (New York), and the Lamb calculator (Calculator Mfg. Co., New York) are less ex- pensive machines devised for figuring payrolls and labor costs. A still simpler device for the same purpose is the Calculacard (New York). The machine called the Calculagraph (New York) is a time clock which automatically computes labor costs. For graphical methods of computation, see pp. 106, 119, 170, 173-185. FINANCIAL ARITHMETIC For the facts which are commonly required in regard to compound interest, sinking funds, etc., see the headings of the tables on pp. 64-68. ELEMENTARY GEOMETRY AND MENSURATION GEOMETRICAL THEOREMS (For geometrical constructions, see p. 101) Right Triangles, a 2 + b 2 = c 2 . (See Fig. 1). /A-f-^=90. 2? 2 = mn. a 2 = me. 6 2 = nc. See also p. 105 and p. 132. Oblique Triangles. (See also pp. 105, 134.) Sum of angles = 180. An exterior angle = sum of the two opposite interior angles. (Fig. 1.) The medians, joining each vertex with the middle point of the opposite side, meet in the center of gravity G (Fig. 2), which trisects each median. The altitudes meet in a point called the orthocenter, 0. The perpendiculars erected at the midpoints of the sides meet in a point C, the center of the circumscribed circle. [In any triangle G, O t and C lie in line, and G is two-thirds of the way from O to C.] FIG. 1. FIG. 2. The bisectors of the angles meet in the center of the inscribed circle (Fig. 3). The largest side of a triangle is opposite the largest angle; it is less than the sum of the other two sides, and greater than their difference. FIG. 3. FIG. 4. Similar Figures. Any two similar figures, in a plane or in space, can be placed in "perspective," that is, so that straight lines joining corresponding points of the two figures will pass through a common point (Fig. 4). That is, of two similar figures, one is merely an enlargement of the other. Assume that each length in one figure is k times the corresponding length in the other; then each area in the first figure is k 2 times the corresponding area in the second, and each volume in the first figure is fc 3 times the corresponding volume in the second. If two lines are cut by a set of parallel lines (or parallel planes) , the corresponding segments are proportional. The Circle. (See also pp. 106, 137.) An angle inscribed in a semicircle is a right angle (Fig. 5). An angle inscribed in a circle, or an angle between a chord and a tangent, is measured by half the intercepted arc (Fig. 6). An angle formed by any two lines which meet a circle is measured by half the sum or half the difference of the intercepted arcs, according as the point of intersection of the lines lies inside (Fig. 7) or outside the circle (Fig. 8). A tangent is perpendicular to the radius drawn to the point of contact. If a variable line through A (Figs. 9 and 10) cuts a circle in P and Q, then 100 ELEMENTARY GEOMETRY AND MENSURATION AP X AQ is constant; in particular, if A is an external point, AP X AQ - AT 2 , where AT is the tangent from A. T FIG. 5. Fio. FIG. 7. FIG. 8. FIG. 9. FIG. 10. The radical axis (Fig. 11) of two circles is a straight line such that the tangents drawn from any point of this line to the two circles are of equal length. If the two circles intersect, the radical axis passes through their points of intersection. In any case, the radical axis bisects the common tangents of the two circles. The three radical axes of a set of three circles meet in a common point. (For equations, see p. 137.) FIG. Dihedral Angles. The dihedral angle between two planes is measured by a plane angle formed by two lines, one in each plane, perpendicular to the edge (Fig. 12). (For solid angles, see p. 110.) In a tetrahedron, or triangular pyramid, the four medians, joining each vertex with the center of gravity of the opposite face, meet in a point, the center of gravity of the tetrahedron; this point is % of the way from any vertex to the center of gravity of the opposite face. The four perpendiculars erected at the circumcenters of the four faces meet in a point, the center of the circumscribed sphere. The four altitudes meet in a point called the orthocenter of the tetrahedron. The planes bisecting the six dihedral angles meet in a point, the center of the inscribed sphere. FIG. 12. FIG. FIG. 14. FIG. 15. FIG. 16. FIG. 17. Regular Polyhedra (see also p. 110): Regular tetrahedron (Fig. 13), bounded by four equilateral triangles; cube (Fig. 14), bounded by six squares; octahedron (Fig. 15), bounded by eight equilateral triangles; dodecahedron (Fig. 16), bounded by twelve regular pentagons; icosahedron (Fig. 17), bounded by twenty equilateral triangles. Figs. 13-17 show how these solids can be made by cutting the surface out of paper and folding it together. The Sphere. (See also p. 109.) If AB is a diameter, any plane perpen- dicular to AB cuts the sphere in a circle, of which A and B are called the poles. A great circle on the sphere is formed by a plane passing through the center. A spherical triangle is bounded by arcs of great circles (see p. GEOMETRICAL CONSTRUCTIONS 101 134). In two polar triangles, each angle in one is tntf fcuppfeme'nt'of the corresponding side in the other. In two symmetrical triangles, the sides and angles of one are equal to the corresponding sides and angles of the other, but arranged in the reverse order (like right-handed and left-handed gloves). GEOMETRICAL CONSTRUCTIONS To Bisect a Line AB (Fig. 18). (a) From A and B as centers, and with equal radii, describe arcs intersecting in P and Q, and draw PQ, which will bisect AB in M. (6) Lay off AC = BD = approximately half of AB, and then bisect CD. To Draw a Parallel to a Given Line 1 Through a Given Point A (Fig. 19). With point A as center draw an arc just touching the line Z; with any point O of the line as center, draw an arc BC with the same radius. Then a line through A touching this arc will be the required parallel. Or, use a straight edge and triangle. Or, use a sheet of celluloid with a set of lines parallel to one edge and about y\ in. apart ruled upon it. >Q 7-X (a.) (b.) FIG. 18. FIG. 19. FIG. 20. To Draw a Perpendicular to a Given Line from a Given Point A Outside the Line (Fig. 20). (a) With A as center, describe an arc cutting the line in R and S, and bisect RS in M . Then M is the foot of the perpen- dicular. (&) If A is nearly opposite one end of the line, take any point B of the line and bisect AB in O ; then with O as center, and OA or OB as radius, draw an arc cutting the line in M . Or, (c) use a straight edge and triangle. /?' P ^5 F*^ ~7Q P 4 B FIG. 21. FiGT22. FIG. 23. To Erect a Perpendicular to a Given Line at a Given Point P. (a) Lay off PR = PS (Fig. 21), and with R and S as centers draw arcs inter- secting at A. Then PA is the required perpendicular. (6) If P is near the end of the line, take any convenient point O (Fig. 22) above the line as center, and with radius OP draw an arc cutting the line in Q. Produce QO to meet the arc in A ; then PA is the required perpendicular, (c) Lay off PB = 4 units of any scale (Fig. 23) ; from P and B as centers lay off PA = 3 and BA = 5; then APE is a right angle. To Divide a Line AB into n Equal Parts (Fig. 24). Through A draw a line AX at any angle, and lay off n equal steps along this line. Connect the last of these divisions with B, and draw parallels through the other divi- 102 ELEMENTARY GEOMETRY AND MENSURATION cdori*. These parallels wili divide the given line into n equal parts. A similar method may be used to divide a line into parts which shall be proportional to any given numbers. / / ^u \ /-r ,' m \ ,,--' Ix., I A I 3 C A A fl FIG. 25. FIG. 26. FIG. 24. To Construct a Mean Proportional (or Geometric Mean) Between Two Lengths, m and n (Fig. 25). Lay off .AB = m and BC = n and construct a semicircle on AC as diameter. Let the perpendicular erected at B meet the circumference at P. Then BP = -\/mn. (See p. 115.) To Divide a Line AB in Extreme and Mean Ratio (the "golden sec- tion"). At one end, B, of the given line (Fig. 26), erect a perpendicular, BO, equal to half AB, and join OA. Along OA lay off OP = OB, and along AB lay off AX = AP. Then X is the required point of division; that is, AX 2 = AB XBX. Numerically, AX = ^(\/5 '- 1)(AB) = 0.618(AB). To Bisect an Angle AOB (Fig. 27). Lay off OA = OB. From A and B as centers, with any convenient radius, draw arcs meeting in M ; then OM is the required bisector. To draw the bisector of an angle when the vertex of the angle is not accessible (Fig. 28). Parallel to the given lines a, 6, and equidistant from them, draw two lines a', &' which intersect; then bisect the angle between a' and 6'. -<* PL. ,-'Ct' FIG. 27. FIG. 28. To Draw a Line Through a Given Point A and in the Direction of the Point of Intersection of Two Given Lines, when this point of inter- section is inaccessible (Fig. 29). Draw any two parallel lines PQ and P'Q' as in the figure; through P' draw a line parallel to PA, and through Q' draw a line parallel to QA; let these lines intersect in A', and draw the line AA'. This line A A' will (if produced) pass through the intersection of the two given lines. To Construct, Approximately, the Length of a Circular Arc (Rankine). In Fig. 30 draw a tangent at A. Prolong the chord BA to C, making AC = H AB. With C as center, and radius CB, . draw arc cutting the tangent in D. Then AD = arc AB, approximately (error about 4 min. in an arc of 60 deg.). Conversely, to find an arc AB on a given circle to equal a given length AD, take E one-fourth of the way from A to D, and with E as center and radius ED draw an arc cutting the circum- ference in B. Then arc AB = AD, approxi- mately. FIG. 30. GEOMETRICAL CONSTRUCTIONS 103 To Inscribe a Hexagon in a Circle (Fig. 31). Step around the cir- cumference with a chord equal to the radius. Or, use a 60-deg. triangle. To Circumscribe a Hexagon About a Circle (Fig. 32). Draw a chord AB equal to the radius. Bisect the arc AB in T. Draw the tangent at T (parallel to AB), meeting OA and OB in P and Q. Then draw a circle with radius OP or OQ and inscribe in it a hex- FIG. 31. FIG. 32. FIG. 33. agon, one side being PQ. To Inscribe an Octagon in a Square (Fig. 33). From the corners as centers, and with radius equal to half the diagonal, draw four arcs, cutting the sides in eight points. The points will be the vertices of the octagon. To Inscribe an Octagon in a Circle. Draw two perpendicular diameters, and bisect each of the quadrant arcs. To Circumscribe an Octagon About a Circle. Draw a square about the circle, and draw the tangents to the circle at the points where the circle is cut by the diagonals of the square. To Construct a Polygon of n Sides, One A 8 Side AB being Given (Fig. 34). With A as FIG. 34. center and AB as radius, draw a semicircle, and divide it into n parts, of which n 2 parts (counting from B) are to be used. Draw rays from A through these points of division, and complete the construction as in the figure (in which n = 7). Note that the center of the polygon must lie in the perpen- dicular bisector of each side. To Draw a Tangent to a Cir- cle from an external point A (Fig. 35). Bisect AC in M; with M as center and radius MC, draw arc cutting circle in P; then P is the FIG. 35. FIG. 36. required point of tangency. To Draw a Common Tangent to Two Given Circles (Fig. 36). Let C and c be the centers and R and r the radii (R > r). From C as center, draw two concentric circles with radii R + r and R r; draw tangents to these circles from c; then draw parallels to these lines at distance r. These paral- lels will be the required common tan- gents. To Draw a Circle Through Three Given Points A, B, C, or to find the center of a given circular arc (Fig. 37). FIG. 37. FIG. 38. Draw the perpendicular bisectors of AB and BC; these will meet in the center, 0. To Draw a Circular Arc Through Three Given Points When the Center is not Available (Fig. 38). With A and B as centers, and chord 104 ELEMENTARY GEOMETRY AND MENSURATION AB as radiua, draw arcs, cut by BC in R and by AC in S. Divide R A into n equal parts, 1, 2, 3, . . . Divide BS into the same number of equal parts, and continue these divisions at 1', 2', 3', ... Connect A with 1', 2', 3', . . and B with 1, 2, 3, . . . Then the points of intersec- tion of corresponding lines will be points of the re- quired arc. (Construction valid only when CA = CB.) To Draw a Circle Through Two Given Points, A, B, and Touch- ing a Given Line, 1 (Fig. FlQ> 39 FlG . 40 39). Let AB meet line I in C. Draw any circle through A and B, and let CT be tangent to this circle from C. Along Z, lay off CP and CQ equal toCT. Then either P or Q is the required point of tangency. (Two solutions.) Note that the center of the required circle lies in the perpendicular bisector of AB. To Draw a Circle Through One Given Point, A, and Touching Two Given Lines, 1 and m (Fig. 40). Draw the bisector of the angle between I and m, and let B be the reflection of A in this line. Then draw a circle through A and B and touching I (or m}, as in preceding con- struction. (Two solutions.) To Draw a Circle Touching Three Given Lines (Fig. 41). Draw the bisec- tors of the three angles; these will meet in the center O. (Four solutions.) The perpendiculars from O to the three lines give the points of tangency. To Draw a Circle Through Two Given Points A, B, and Touching a Given Circle (Fig. 42). Draw any circle through A and B, cutting the given circle in C and D. Let AB and CD meet in E, and let ET be tangent from E to the circle just drawn. With E as center, and radius ET, draw an arc cutting the given circle in P and Q. Either P or Q is the required point of contact. (Two solutions.) To Draw a Circle Through One Given Point, A, and Touching Two Given Circles (Fig. 43). Let S be a center of similitude for the two given circles, that is, the point of intersection of two external (or internal) common tangents. Through -S draw any line cutting one circle in two points, the nearer of which shall be called P, and the other in two points, the more remote of which shall be called Q. Through A, P, Q FIG. 41. FIG. 42. FIG. 43. LENGTHS AND AREAS OF PLANE FIGURES 105 draw a circle cutting S A in B. Then draw a circle through A and B and touching one of the given circles (see preceding construction). This circle will touch the other given circle also. (Four solutions.) To Draw an Annulus Which Shall Contain a Given Number of Equal Contiguous Circles (Fig. 44). (An annulus is a ring-shaped area enclosed between two concentric circles.) Let R + r and R r be the inner and outer radii of the annulus, r being the radius of each of the n circles. Then the required relation between these quantities is given by r = R sin (180/n), or r = JT IG 44 (R + r)[sin (180%01/U + sin (180%*)]. For methods of constructing ellipses and other curves, see pp. 139-156. LENGTHS AND AREAS OF PLANE FIGURES Right Triangle (Fig. 45). a 2 + 6 2 = c 2 . Area = tf ab = Ma 2 cot A = H& 2 tan A = He 2 sin 2 A. Equilateral Triangle (Fig. 46). Area = Ma 2 \/3 = 0.43301a 2 . FIG. 45. a FIG. 47. Any Triangle (Fig. 47). s = # (a + b + c), t = H(m x + m 2 r =-\/(s a)(s 6)(s c)/s = radius inscribed circle, R = W a/ sin -A = },& /sin B = ^c/sin C = radius circumscribed circle; Area = H base X altitude = \toh = tfab sin C = rs = abc/lR = Vs(s -o)(s -&)( - c) = ^ \*(* - mi) (< - = r 2 cot ft A cot H B cot ^ C* = 2# 2 sin A sin J5 sin C = W { (zi2/2 22/1) + (Z2Z/3 0:32/2) + (zsl/i 12/3) } , where (zii 2/i). (2, 1/2), (xs, 1/3) are co-ordinates of vertices. See also p. 134. FIG. 48. FIG. 49. FIG. 50. Rectangle (Fig. 48). Area = ab = &D 2 sin u. [u = angle between diagonals D, D.] Rhombus (Fig. 49). Area = a 2 sin C = tfDiDz. [C = angle between two adjacent sides; DI, Dz = diagonals.] Parallelogram (Fig. 50). Area = bh = ab sin C = MDiD* sin u. [u = angle between diagonals DI andZ) 2 ;Z>i 2 + Z> 2 2 = 2(a 2 + 6 2 )]. Trapezoid (Fig. 51). Area = H(a + b)h = WDiDt sin u. [Bases a and b are parallel; u = angle between diagonals DI and D*.] 106 ELEMENTARY GEOMETRY AND MENSURATION sn u = c Quadrilateral Inscribed in a Circle (Fig. 52). Area V(s - a)(s - 6)(s - c)(s - d) = tf(ac -+ bd)sin u\ s= ft (a Any Quadrilateral (Fig. 53). Area = WDiDi sin u. NOTE, a 2 + 6 2 + c 2 + d z = Z>i 2 + D 2 2 + 4m 2 , where m = distance between midpoints of D\ and Dz. Polygons. See table, p. 39. FIG. 52. FIG. 53. Circle. Area = -n-r 2 = ^O = y^Cd Here r = radius, d = diam., C = circumference = 2irr = ird Annulus (Fig. 54). Area = ir(R 2 - r 2 ) = 7r(J> 2 - d 2 )/4 R' = mean radius = tf(R + r), and 6 = R r. Sector (Fig. 55). Area = Mrs = 7rr 2 (^/360) = y%r z rad A, where rad A = radian measure of angle A, and s = length of arc = r rad A (table, p. 44). Segment (Fig. 56). Area = J^r 2 (rad A - sin A) = yi[r(s c) + ch], where rad A = radian measure of angle A (table, pp. 34-35, 44). For small arcs, s = J.$(8c' c), where c' = chord of half the are. (Huygens's approximation.) NOTE, c = 2\/h(d h) ; c' = \/dh or d c' 2 /h, where d = diameter of circle ; h =r (1 cos l /*tA), s 2r rad %A. Ribbon bounded by two parallel curves (Fig. 57). If a straight line AB moves so that it is always per- pendicular to the path traced by its middle point G, FIG. 55. = 0.785398d 2 (table, p. 30). (table, p. 28). = 2-n-R'b, where FIG. 56. FIG. 57. then the area of the ribbon or strip thus generated is equal to the length of AB times the length of the path traced by G. (It is assumed that the radius of curvature of G's path is never less than tf AB, so that successive positions of the generating line will not intersect.) Simpson's Rule (Fig. 58). Divide the given area into n panels (where n is some even number) by means of n + 1 parallel lines, called ordinates, drawn at constant dis- tance h apart; and denote the lengths of these ordinates by 3/0, 2/i, 2/2, . . , 2/n. (Note that 2/o or y n may be zero.) Then Area = ^h[(y + y n ) + 4(yi +2/3+2/5. . ) + 2(2/2 + 2/4 + 2/6- . ) ]. approx. The greater FIG. 58. the number of divisions, the more accurate the result. Note: Taking y = f(x) , where x varies from x = a to x = 6, and h = (b a) /n, then the error = ~ ^ & ~^ f""(X), where f""(X) is the value of the fourth de- loO 71 rivative of f(x) for some (unknown) value, x = X, between a and 6. SURFACES AND VOLUMES OF SOLIDS 107 Ellipse (Fig. 59; see also p. 140). Area of ellipse = trab. Area of shaded segment = xy + ab sin" 1 (x/a). Length of perimeter of ellipse = ir(a + b)K, where K = [1 + Y*m z + H*m 4 + ^sem 6 + ...], m = (a - 6)/(a + 6). Form =0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 K= 1.002 1.010 1.023 1.040 1.064 1.092 1.127 1.168 1.216 1.273 (_.__ a _..J FIG. 60. Hyperbola (Fig. 60; see also p. 144). In any hyperbola, shaded area A ab loge ( (-") In an equilateral hyperbola (a = &), area A = \a b/ o 8 sirih- l (y/d) = o 2 cosh- l (x/d). For tables of hyperbolic functions, see p. 60. Here x and y are co-ordinates of point P. Parabola (Fig. 61; see also p. 138). Shaded area A = ftch. In Fig. 62, length of arc OP = s = tyPT + typ log e cot ^u. Here c = any chord; p = semi-latus rectum; PT = tangent at P. Note: OT = OM = x. FIG. 61. FIG. 62. Other Curves. For lengths and areas, see pp. 147-156. SURFACES AND VOLUMES OF SOLIDS Regular Prism (Fig. 63). Volume = ^nrah = Bh. Lateral area = nah = Ph. Here n = number of sides; B = area of base; P = perimeter of base. Right Circular Cylinder (Fig. 64). Volume = irr 2 h = Bh. Lateral area = lirrh = Ph. Here B = area of base; P = perimeter of base. FIG. 63. FIG. 64. FIG. 65. FIG. 66. Truncated Right Circular Cylinder (Fig. 65). Volume = -n-r 2 h = Bh. Lateral area = 2wrh = Ph. Here h = mean height = tf(hi + ta) ; B = area of base; P = perimeter of base. 108 ELEMENTARY GEOMETRY AND MENSURATION Any Prism or Cylinder (Fig. 66). Volume = Bh = NL Lateral area = Ql. Here I = length of an element or lateral edge; B = area of base; N = area of normal section; Q = perimeter of normal section. Any Truncated Prism or Cylinder (Fig. 67). Volume = Nl. Lateral area = Qk. Here I = distance between centers of gravity of areas of the two bases; k = distance between centers of gravity of perimeters of the two bases; N = area of normal section; Q = perimeter of normal section. For a trun- cated triangular prism with lateral edges a,b,c, I = k = \i(a +6 + c). Note: I and k will always be parallel to the elements. FIG. 67. FIG. FIG. 69. FIG. 70. Special Ungula of a right circular cylinder. (Fig. 68.). Volume = Lateral area = 2rH. r = radius. (Upper surface is a semi-ellipse.) Any Ungula of a right circular cylinder. (Figs. 69 and 70.) Volume = H(Ha 3 c)/(r c) = H[a(r* - ^a 2 ) r 2 crad u]/(r c). Lateral area = H(2ra cs)/(r c) = 2rH(a c rad u)/(r c). If base is greater (less) than a semicircle, use + ( ) sign, r = radius of base; B = area of base; s= arc of base; u= half the angle subtended by arc s at center; rad u = radian measure of angle u (see table, p. 44). Hollow Cylinder (right and circular). Volume = 7rh(R* -r 2 ) =Trhb(D- b) = Trhb(d + 6) = MD' = irhb (R + r). Here h = altitude; r,R(d,D) = inner and outer radii (diameters) ; b = thickness = R r; D' = mean diam. =ty(d + D) =D -b =d+6. Regular Pyramid (Fig. 71). Volume = 1$ altitude X area of base ^hran. base = ^san. Here r = radius of inscribed circle; a = side (of regular polygon) ; n number of sides; s = \/r* + h 2 . Vertex of pyramid directly above center of base. Right Circular Cone. Volume = H-irr z h. Lateral area = TTTS. Here r =* radius of base; h = altitude; s = slant height = \/r 2 + h 2 . Frustum of Regular Pyramid (Fig. 72). Volume = Uhran[l + (a'/o) + (a' /)*] Lateral area = slant height X half sum of perimeters of bases = slant height X perimeter of mid-section = J /isn(r + r'). Here r,r' = radii FIG. 71. Lateral area FIG. 72. FIG. 73. slant height X perimeter of SURFACES AND VOLUMES OF SOLIDS 109 of inscribed circles; s = V (r r') 2 + ft 2 ; a,a r = sides of lower and upper bases; n = number of sides. Frustum of Right Circular Cone (Fig. 73). Volume = Lateral area = irs(r + r') ;> = V(r - r') 2 + ft 2 . Any Pyramid or Cone. Volume = ftBh. B = area of base; h = perpen- dicular distance from vertex to plane in which base lies. Any Pyramidal or Conical Frustum (Fig. 74). Volume = HftCB + VBB~' + B") = XhB[l + (P'/P) + (P'/P) 2 ]- Here B, B' = areas of lower and upper bases; P, P' = perimeters of lower and upper bases. FIG. 74. FIG. 75. FIQ. 76. Obelisk (Frustum of a rectangular pyramid. Fig. 75). Volume = ^ft[(2a + ai)6 + (2ai + a) 61] = Kh[ab + (a + ai) (6 + 61) + Wedge (Rectangular base; ai parallel to a,a and at distance ft above base. Fig. 76). Volume = }6ft6(2a + ai). Sphere. Volume = V = ^Trr 3 =. 4.188790r 3 = H^ 3 = 0.523599d 8 (table, p. 36) = % volume of circumscribed cylinder. Area = A 4rnr z = four great circles (table, p. 30) = ird 2 = 3.14159d 2 = lateral area of circumscribed cylinder. Here r = radius; d = 2r = diameter = ^/67/7r = 1.24070 i/7 0.56419\/Z- Hollow Sphere, or spherical shell. Volume = Hir(R 3 r 3 ) = H7r(D 3 d 8 ) = 4irRiH + lint*. Here -R,r = outer and inner radii; D,d = outer and inner diameters; t = thickness = R r; RI = mean radius = Spherical Segment of One Base. Zone (spher- ical "cap" of Fig. 78). Volume = H7rft(3o 2 + ft 2 ) = H7rft 2 (3r ft) (table, p. 38). Lateral area (of zone) = 27rrft= 7r(a. 2 + ft 2 ). Note: a 2 = ft(2r - ft), where r = radius of sphere. Any Spherical Segment. Zone (Fig. 77). Vol- ume = ^?rft(3a 2 + 3ai 2 + ft 2 ). Lateral area (zone) = 27rrft. Here r = radius of sphere. If the inscribed frustum of a cone be removed from the spherical seg- ment, the volume remaining is Mirhc 2 , where c = slant height of frustum = \/ft 2 + (p> ~ i) 2 - Spherical Sector (Fig. 78). Volume = W X area Total area = area of cap + area of cone ft(2r - ft). of cap 2irrh + vra. Note: o 2 110 ELEMENTARY GEOMETRY AND MENSURATION (Fig. area Spherical Wedge bounded by two plane semicircles and a lune. 79.) Volume of wedge -r- volume of sphere = w/360 . Area of lune of sphere = w/360. u = dihedral angle of the wedge. Spherical Triangle bounded by arcs of three great circles. (Fig. 80.) Area of triangle = Trr 2 E/l80 = area of octant X #/90. E = spherical excess = 180 (A + B + C), where A, B, and C are angles of the triangle. See also p. 134. Solid Angles. Any portion of a spherical surface subtends what is called a solid angle at the center of the sphere. If the area of the given portion of spherical surface is equal to the square of the radius, the subtended solid angle is called a steradian, and this is commonly taken as the unit. The entire solid angle about the center is called a steregon, so that 4r steradians = 1 steregon. A so-called "solid right angle" is the solid angle sub- tended by a quadrantal (or trirectangular) spherical triangle, and a "spherical degree" (now little used) is a solid angle equal to ^o of a solid right angle. Hence 720 spherical degrees = 1 steregon, or TT stera- dians = 180 spherical degrees. If u = the angle which an element of a cone makes with its axis, then the solid angle 'of the cone contains 2?r(l cos u) steradians. Regular Polyhedra. A = area of surface; V = volume; a = edge. Name of solid (see p. 100) Bounded by A/a 2 V/a* Tetrahedron ............................... 4 triangles 1.7321 0.1179 Cube ...................................... 6 squares 6.0000 1.0000 Octahedron ................................ 8 triangles 3.4641 0.4714 Dodecahedron ............................ . . 12 pentagons 20. 6457 7. 6631 Icosahedron .............................. 20 triangles 8.6603 2.1817 Ellipsoid (Fig. 81). Volume = tynrdbc, where a, b, c = semi-axes. Spheroid (or ellipsoid of revolution). The volume of any segment made by two planes perpendicular to the axis of revolution may be found ac- curately by the prismoidal formula (p. 111). FIG. 79. FIG. 80. FIG. 81. FIG. 82. FIG. 83. FIG. 84. Paraboloid of Revolution (Fig. 82). Volume = y^rr^h = ^ volume of circumscribed cylinder. Segment of Paraboloid of Revolution (Bases perpendicular to axis, Fig. 83). Volume of segment = ynr(R* + r z }h. Barrels or Casks (Fig. 84), Volume = ],i 2 irh(2D 2 + d 2 ) approx. for cir- cular staves. Volume = Wvrh(2D 2 + Dd + ^d 2 ) exactly for parabolic staves. SURFACES AND VOLUMES OF SOLIDS 111 FIG. 85. For a standing cask, partially full, compute contents by the prismoidal formula, p. 111. Roughly, the num- ber of gallons, G, in a cask is given by G = 0.0034?i 2 /i, where n = number of inches in the mean diameter, or H(-D + d), and h = number of inches in the height. Torus, or Anchor Ring (Fig. 85). Volume = 2:r 2 cr 2 . Area = 4vr 2 cr (Proof by theorems of Pappus). Theorems of Pappus. 1. Assume that a plane figure, area A, revolves about an axis in its plane but not cutting it; and let s = length of circular arc traced by its center of gravity. Then volume of the solid generated by A is V = As. For a complete revolution, V 2irrA, where r = distance from axis to center of gravity of A. 2. Assume that a plane curve, length I, revolves about an axis in its plane but not cutting it; and lets = length of circular arc traced by its center of gravity. Then area of the surface generated by I is S = Is. For a complete revolution, S = 2-irrl, where r = distance from axis to center of gravity of I. NOTE. If Vi or Si about any axis is known, then Vz or 2 about any parallel axis can be readily computed when the distance between the axes is known. Generalized Theorems of Pappus. Consider any curved path of length s. If (1) a plane figure, area A [or (2) a plane curve, length I] moves so that its center of gravity slides along this curved path (Fig. 86), while the plane of A [or I] remains always perpendicular to the path, then (1) the volume generated by A is V = As [and (2) the area generated by I is S Is]. The path is assumed to curve so gradually that successive positions of A [or I] will not intersect. The Prismoidal Formula (Fig. 87). Volume =Uh(A +B +.4M), where h = altitude, A and B = areas of bases and M = area of a plane section midway between the bases. This formula is exactly true for any solid lying between two parallel planes and such that the area of a sec- tion at distance x from Fm> g7 FlG> gg one of these planes is expressible as a polynomial of not higher than the third degree in x. approximately true for many other solids. Simpson's Rule may be applied to finding volumes, i'f the ordinates 2/i, 2/2, be interpreted as the areas of plane sections, at constant distance h apart (p. 106). Cavalieri's Theorem. Assume two solids to have their bases in the same plane. If the plane section of one solid at every distance x above the base is equal in area to the plane section of the other solid at the same dis- tance x above the base, then the volumes of the two solids will be equal. See Fig. 88. FIG. 86. It is ALGEBRA FORMAL ALGEBRA Notation. The main points of separation in a simple algebraic expres- sion are the + and signs. Thus,, a + b X c d + x -)- y is to be inter- preted as a + (b X c) (d -5- 3) + y. In other words, the range of opera- tion of the symbols X and -i- extends only so far as the next^+ or sign. As between the signs X and -f- themselves, a -f- b X c means, properly speak- ing, a -r- (b X c); that is, the -5- sign is the stronger separative; but this rule is not always strictly followed, and in order to avoid ambiguity it is better to use the parentheses. The range of influence of exponents and radical signs extends only over the next, adjacent quantity. Thus, 2ax 3 means 2a(x 3 ), and \^2ax means (\/2) (ax). Instead of \/2ax, it is safer, however, to write \/2'ax, or, bet- ter, ox's/2- Any expression within parentheses is to be treated as a single quantity. A horizontal bar serves the same purpose as parentheses. The notation a-b, or simply ab, means a X b; and a: b, or a/b, means a -f- b. The symbol |a| means the "absolute value of a," regardless of sign; thus, |-2| = | + 2| =2. The symbol nl (where n is a whole number) is read: "n factorial," and means the product of the natural numbers from 1 to n, inclusive. Thus 1! = 1; 2! = 1 X 2; 3! = 1 X 2 X 3; 4! = 1 X 2 X 3 X 4 /etc. The symbol ^ or =f means, "not equal to"; means "plus or minus." The symbol is som'etimes used for "approximately equal to." Addition and Subtraction, a + b = b + a. (a + b) + c = a + (b + c). a - ( - b) = a + b. a - a = 0. a + (x y + z) = a+x y+z. a (x^ y + z) = a x + y z. A minus sign preceding a parenthesis operates' to reverse the sign of every term within, when the parentheses are removed. Multiplication and Simple Factoring, ab = ba. (ab)c = a(bc). a(b -f- c) = ab + ac. a(b c) = ab ac. Also, a X ( b) = ab, and ( o) X ( b) = ab; "unlike signs give minus; like signs give plus." (a + 6) (a - 6) = a 2 - b 2 . (a + b) 2 ='a 2 + 2ab + b 2 , (a - 6) 2 =a 2 - 2ab + 6 2 . (a + &) 3 = o 3 + 3o 2 & + 3a& 2 + 6 3 , (a - 6) 3 = a 3 -3a 2 &+ 3a& 2 - 6 3 ; etc. (See table of binomial coefficients, p. 39; also p. 114.) 2 _ & 2 = (o - &)(o + 6), a 3 - 6 3 = (o - 6) (a 2 + ab + b 2 ). a n - b n = (a - 6) (a 71 - 1 + a n - 2 6 + a n ~ 3 6 2 + . . . + ab n ~ 2 + 6"- 1 ). a n + b n is factorable by a + 6 only when n is odd ; thus, a a 4. &3 = ( O ._j_ 5)( a 2 _ ab + b 2 ), a e + &5 = ( _|_ 6) (o 4 - a 3 b + a 2 b 2 - ab 3 + b 4 ) ; etc. The following transformation is sometimes useful : f / b \ 2 (Vb^^4a~c\ 2 1 ax* + bx+c=a[(x + -) -( ^ ) J. ma + mb -\-rnc a+b+c Fractions. If w is not zero, - - = ; that is, mx + my x -\- y both numerator and denominator of a fraction may be multiplied or divided 112 FORMAL ALGEBRA 113 by any quantity different from zero, without altering the value of the fraction. To add two fractions, reduce each to a common denominator, and add the a x ay bx ay + bx numerators: r + ~ = ; -- H r~ = - ; - b y by by by a x ax a ax ax To multiply two fractions: T X - = r~; T X z = -r X- = ~r. b y by b bib To divide one fraction by another, invert the divisor and multiply: o ^5 _ ja V 2/ _ay _a _._ _ a 1 _ ^ t ~~ T -^ ~"~ 1 > 1 X /\ b y b . x bx b b x bx Ratio and Proportion. The notation a:b: :c:d, which is now passing out of use, is read: "a is to & as c is to d," and means simply (a/6) = (c/d), or ad = be. a and d are called the "extremes," 6 and c the "means," and d the "fourth proportional" to a, b, and c. The "mean proportional" between two numbers is the square root of their product; also called the "geometric mean" of the numbers (p. 115). If a/6 =' c/d, then (a -{-&)/& = (c + d)/d, and (a - &)/& = (c d)/d; whence also, (a -\- 6) /(a - 6) = (c+d)/(c-d). I*a/x=b/y=c/z = . . . = r, then Variation. The notation x cc y is read: "a; varies directly as y," or "x is directly proportional to y," and means a; = ky, where k is some constant. To determine the constant k, it is sufficient to know any pair of values, as x\ and 2/1, which belong together; then o?i = kyi, and hence x/xi = y/yi, or = (r 1, and approaches if a < 1 (a being always positive). Graphs, p. 174; series, p. 160. Radicals. Except in the simple cases of square root and cube root, radical signs should always be replaced by fractional exponents: "v/a = a n . (Va) n = (a 1/n ) = a. If n is odd, \/^a = - -\/a' t but if n is even, V a is imaginary. Every positive number a has two square roots, one positive and the other negative; but the notation \/a always means the positive root; thus, v9 = 3;_ V9 = 3. If the denominator of a fraction is of the form va + v b, it is possible to "rationalize the denominator" by multiplying both numerator and denominator by \/a + \/&. Thus: A/a + A/6 = (Va +.Vb)(Va + A/6) _ a + b + 2A/a& A/a - A/6 (A/^ - A/6)(Va + V&) ~ 0-6 Logarithms. (For the use of logarithms in numerical computation, see p. 91.) The logarithm of a (positive) number N is the exponent of that power to which the base (10 or e) must be raised to produce N. Thus, x = logio N means that 10* = N, and x = Iog 8 N means that e x = N. Loga- rithms to base 10 are called common, denary, or Briggsian logarithms. For table of 4-pIace common logarithms see pp. 40-43. 114 ALGEBRA Logarithms to base e are called hyperbolic, natural, or Napierian logar- ithms. Here e = 1 + 1 + 1/2! + 1 /3! + 1/4! + . . . = 2.718281828459. . . For table of 4-place hyperbolic logarithms see pp. 58, 59. If the subscript 10 or e is omitted, the base must be inferred from the context, the base 10 being used in numerical computation, and the base e in theoretical work. In either system, log (o&) = log a + log b log (a n ) = n log a log = log (0/6) = log a log b log (V / a~) = (1/w) log a log 1=0 log (1/n) = log n log (base) = 1 log co = oo The two systems are related as follows: M= 0.4342944819 . . .; Iog e 10 = 1/Af = 2.3025850930. . . 0.4343 logez; log e x = 2.3026 Iogi z. For tables of multiples of M and 1/Af, see p. 62. For graphs of the logar- ithmic and exponential functions, see p. 174; series, p. 160. The Binomial Theorem. (For table of binomial coefficients, see p. 39 and p. 116.) _ . N n(n - 1) n(n - l)(n - 2) Let (n)l - n, (n), - - -* (), - 1X2X3 = --- 1X2X3X4 Then, for any value of n, provided 1 x \ < 1, (1 + z) n = 1 + (n)ix + (n) 2 z 2 + (n) 3 * 3 + (n) 4 * 4 + . .. . (If n is a positive integer, the series breaks off with the term in x n , and is valid without restrictions on x, see p. 112.) The most useful special cases are the following: (bl < i) (1 + o:) 3 = (1 + xY* = 1 + 128 with corresponding formulae for \/l x, etc., obtained by reversing the signs of the odd powers of x. Also, provided |6| < |a|: (a + 6) n = a n ( 1 where (n)i, (71)2, etc., have the values given above. Arithmetical Progression. In an arithmetical progression, a; a + d\ a + 2d] a + 3d; . . ., each term is obtained from the preceding term by adding a constant, called the constant difference, d. If n is the number of terms, the last term is I = a -j- (n l)d; the "average" term is H( + 0{ FORMAL ALGEBRA 115 and the sum of the n terms is n times the average term, or S = ftn(a + Z). The arithmetical mean between a and b is (a + b)/2. Geometrical Progression. In a geometrical progression, o; or; or 2 ; or 8 ; . . . , each term is obtained from the preceding term by multiplying by a constant, called the constant ratio, r. The nth term is ar n ~ l . The sum of the first n terms is S = a(r n - l)/(r - 1) = a(l - r n )/(l - r). If r is a positive or negative fraction, that is, if 1 < r < +1, then r n will approach zero as n increases, and the sum of n terms will approach o/(l r) as a limit. The geometric mean betweep a and 6 is\/~ab; also called the mean proportional between a and 6 (p. 113; construction, p. 102). The harmonic mean between a and 6 is 2ab/(a + b). Summation of Certain Series by Second and Third Differences. Let 01, a2, as, . . . On be any series of n numbers, as in the first column of the adjoining scheme. By subtracting each number from the next following, form the column Jo d fd of "first differences," and by repeating this process, form the columns of second, third, etc., differences. If the fc la kth differences are all equal, so that subsequent differ- M & ences are all zero, the original series is called an arithme- "27 37 is tical series of the fcth order. In this special case the _ g 1 y -12 series can be summed as follows: Denote the numbers 1 i ~ 6 Q which stand at the head of the successive columns of 9 1 9 6 differences by />',>", D"', .... Then the nth term of 8 7 ' the series is a n , and the sum of the first n terms is S n , where (n - 1 X & (n - l)(n -2)(n - n(n - 1) , ' n(n-l)(n-2) D 1X2X3 *>n 1X2X3 n(n-l)(n-2)(n-3) , 1X2X3X4 If the series is, for example, of the third order, each of these formulae will stop with the term involving >'"; and only a few terms of the series are required for the computation of the D's. (Differentials, p. 159.) Sum of the Squares or Cubes of the First n Natural Numbers. 1+2+3 + . . . + (n - 1) + n = %n(n + 1). 1 2 + 22 + 3 2 + . . . + (n - I) 2 + n 2 = fcn(n + l)(2n + 1). 1 3 + 2 3 + 3 3 + . . . + (n - I) 3 + n 3 = [j*n(n + I)] 2 . Formula for Interpolation by Second Differences. In any ordinary table giving a quantity y as a function of a variable x, let it be required to find the value of y corresponding to a value of x which is not given directly in the table, but which lies between two tabulated values, as x\ and xz. If x = xi + md, where d = xz x\ = the constant interval between two suc- cessive x's, and m is some proper fraction, then the corresponding value of y will be given by the formula m(m - 1) m(m - l)(m - 2) y = Vl + mD + 1X2 D + - : x 2'" < 8 (or D" " < 12, or D" '" < 16), the term involving D'" (or D" ", or D" '") can be neglected. Binomial Coefficients for Fractional Values of m m (m). (m), (m) 4 (m)s 0.0 - 0.0000 0.0000 -0 0000 00000 O.I - 0.0450 0.0285 - 0.0207 0.0161 0.2 - 0.0800 0.0480 - 0336 0255 0.3 -0.1050 0595 - 0402 0297 0.4 - 0.1200 0.0640 - 0.0416 0300 0.5 - 0.1250 0.0625 - 0.0391 0.0273 0.6 - 0.1200 0560 - 0.0336 0.0228 0.7 - 0.1050 0455 - 0.0262 0.0173 0.8 - 0.0800 0.0320 - 0.0176 0113 0.9 - 0.0450 0.0165 . - 0.0087 0.0054 - Here m(m - , N (). w(m-l)(m-2)(m-3) ' 6tC ' 1X2 1X2X3 1X2X3X4 Compare p. 39. Permutations. The number of possible permutations or arrangements of n different elements is 1 X 2 X 3 X . . . X n = n\ (read:"n factorial"). If among the n elements there are p equal ones of one sort, q equal ones of another sort, r equal ones of a third sort, etc., then the number of possible permutations is (nl)/(p\ X q\ X rl X . . .), where p + g + r + . . . = n. Combinations. The number of possible combinations or groups of n elements taken r at a time (without repetition of any element within any one group), is [n(n - l)(n - 2)(w - 3) . . . (n - r + l)]/(r!) == (n) r . (See table of binomial coefficients, p. 39.) If repetitions are allowed, so that a group, for example, may contain as many as r equal elements, then the number of combinations of n elements taken r at a time is (m) r , where m = n + r - 1. NOTE: (n)i + (n) a + . . . + (n) = 2 - 1. SOLUTION OF EQUATIONS IN ONE UNKNOWN QUANTITY Roots of an Equation. An equation containing a single variable x will in general be true for some values of x and false for other values. Any value of x for which the equation is true is called a root of the equation. To "solve" an equation means to find all its roots. Any root of an equation, when substituted therein for x, will "satisfy" the equation. An equation which is true for all values of x, like (x + I) 2 = x z + 2x +1, is called an identity [often written (x + I) 2 s x* + 2x + 1]. Types of Equations. (a) Algebraic Equations: of the first degree (linear), e.gr., 2x + 6 =0 (root: x = 3); of the second degree (quadratic), e.g., x z 2x 3 =0 (roots: 1, 3); of the third degree (cubic), e.g., x 3 - 6x 2 + 5x + 12 =0 (roots: - 1, 3, 4). SOLUTION OF EQUATIONS IN ONE UNKNOWN QUANTITY 117 (6) Transcendental Equations: exponential equations, e.g., 2 X = 32 (root: x = 5); 2 X = 32 (no root); trigonometric equations, e.g., 10 sin x sin 3x = 4 (roots: 30, 150). Legitimate Operations on Equations. An equation which is true for a particular value of x will remain true for that value of x after any one of the following operations is performed: Adding any quantity to both sides; subtracting any quantity from both sides; transposing any term from one side to the other, provided its sign be changed; multiplying or dividing both sides by any quantity which is not zero; changing the signs of all the terms; raising both sides to any positive integral power; extracting any odd root of both sides; extracting any even root of both sides, provided the sign is used; taking the logarithms of both sides (both sides being positive) ; taking the sin, cos, tan, etc., of both sides. Notice, however, that the new equation obtained by some of these operations may possess "additional roots" which did not belong to the original equation. This occurs especially when both sides are squared; thus, x = 2 has only one root, namely, 2; but z 2 =- 4, obtained by squaring, has not only the root 2 but also another root, + 2. Equations of the First Degree (Linear Equations). Solution: Collect all the terms involving x on one side of the equation, thus: ax b, where a and b are known numbers. Then divide through by the coefficient of x, obtaining x = b/a as the root. Equations of the Second Degree (Quadratic Equations). Solution: Throw the equation into the standard form ax 2 + bx + c = 0. Then the two roots are: _ - 6 + Vb* - 4ac -b -Vb* -4ac Xl= ~ -2aT ** = -^a~ The roots are real-and-distinct, coincident, or imaginary, according as 6 2 4ac is positive, zero, or negative. The sum of the roots is x\ + xt = b/a] the product of the roots is x\xz = c/a. GRAPHICAL SOLUTION. Write the equation in the form z 2 = px + q, and plot the parabola yi = x 2 , and the straight line yi = px + q. The abscissae of the points of intersection will be the roots of the equation. If the line does not cut the parabola, the roots are imaginary. Equations of the Third Degree with Term in x 2 Absent. Solution: After dividing through by the coefficient of x 3 fc any equation of this type can be written re 3 = Ax + B. Letp = A/3 and q = B/2. The general solu- tion is as follows: Case 1. q 2 p 3 positive. One root is real, namely zj = %/q + Vq^ p 3 + ^/q - Vq*~^ P 3 ; the other two roofs are imaginary. Case 2. g 2 p 3 = zero. Three roots real, but two of them equal. Case 3. g 2 p 5 negative. All three roots real and distinct. Determine an angle u between and 180, such that cos u = q/(pV^p). Then xi = 2Vpcos (w/3), x z = 2^/p cos (w/3 + 120), x z = 2\/pcos (w/3 + 240). GRAPHICAL SOLUTION. Plot the curve yi = x 3 , and the straight line yt = Ax + B. The abscissae of the points of intersection will be the roots of the equation. Equations of the Third Degree (General Case). Solution: The gen- eral'cubic equation, after dividing through by the coefficient of the highest 118 ALGEBRA ,. power, may be written rr 3 + ax* -f bx -f c = 0. To get rid of the term in a; 2 , let x = xi a/3. The equation then becomes #i 3 = Ax\ + B, where A = 3(a/3) 2 - 6, and B = - 2(a/3) 3 + 6(a/3) - c. Solve this equation for xi, by the method above, and then find x itself from x = xi (a/3). GRAPHICAL SOLUTION. Without getting rid of the term in x 2 , write the equation in the form x 3 = - a[x + (&/2a)p + [a(6/2a) 2 - c], and solve by the graphical method. General Properties of Algebraic Equations. An algebraic equation of the nth degree in x is an equation of the type aox n + aix n ~ l + oax 71 " 2 + . . . -fa n -iz+ a n = where the a's are any given numbers (ao not zero), the expression on the left being called a polynomial of the nth degree in x. Such an equation will, in general, have n roots; but some of these n roots may be equal, and some may be imaginary. Imaginary roots always occur in pairs. If the equation is written in the form: (a polynomial in x) = 0, then (1) if a is a root of the equation, x a is a factor of the polynomial; (2) if the polynomial can be factored in the form (x p)(x q)(x r) . . . = 0, each of the quantities p, q, r, . . . is a root of the equation; (3) if x is very large (either positive or negative) , the higher powers of x are the most impor- tant; (4) if x is very small, the higher powers may be neglected. Short Method of Substitution in a Polynomial. To find the value of 4x 14z 3 + 23x 26 when x = 3, for example, first arrange the terms in order of descending powers of x, and write the detached coefficients, with their signs, in a row, taking care to supply a zero coefficient for any missing term, in- 4 14 23 26 (3 eluding the constant term. Then, beginning 12618 15 at the left, bring down the first coefficient; - multiply this by 3, and add to the second 4 26 511 coefficient; multiply this result by 3 again, and add to the third coefficient; and so on. The final result, 11, is the value of the polynomial when x = 3. Short Method of Dividing a Polynomial by x a. The device just explained gives not only the value of the polynomial when x = 3, but also the result of dividing the polynomial by x 3. Thus, in the case illustrated, the quotient is 4o; 3 2x 2 Qx + 5 and the remainder is 11. That is, 4z - 14z 3 + Ox 2 + 23x - 26 = (x - 3)(4z 3 - 2z 2 - 6x + 5) - 11. Exponential Equations. To solve an equation of the form a* = 6, take the logarithms of both sides: x log a = log 6, whence x = (log 6) /(log a). For example, if 3* = 0.4, x = log 0.4/log 3 = (0.6021 - 1)/0.4771 = 0.3979/0.4771 = 0.8340. Notice that the complete logarithm must be taken, not merely the mantissa. Trigonometric Equations. (1) To solve a cos x + 6 sin x = c, where a and b are positive: Find the acute angle u for which tan u = b/a, and the angle v (between and 180) for which cos v = c/\/a z + 6 2 . Then xi = u + v and xz = u v are roots of the equation. (2) To solve a cos x b sin x = c, where a and 6 are positive: Find u and v as above. Then x\ = (u + v) and xz = (u v) are roots of the equation. General Method of Solution by Trial and Error. This method is applicable to a numerical equation of any form, and can be carried out to any desired degree of approximation. It is especially useful when a first approximation to a root is already known, Write the equation i^ the form SOLUTION OF SIMULTANEOUS EQUATIONS 119 f(x) = 0, where /(x) means any function of x, and plot the curve y = f(x) for a sufficient number of values of x to obtain a general idea of the shape of the curve. Then pick out the regions in which the curve appears to cross the axis of x, and plot the curve more accurately in each of these regions. Thus, 2 = XQ *2, . . . v n = XQ x n are called the residuals of the observed values with respect to XQ, and their absolute values (that is, their numerical values without regard to sign) are denoted by \vi\, \v^\, . . . |t> n |. [It can be shown that the sum of the squares of the residuals with respect to XQ is smaller than the sum of the squares of the residuals with respect to any other value X'Q- hence the name of the method: "least squares."] The quantities r and TQ, defined exactly by Bessel's formulae: 0.6745 n(n - 1) or given approximately by the simpler formulae of Peters: ' 8453 (M + H + . . + W), are called the probable error of a single observation (r), and the probable error of the mean (T-Q), for the given series of observations. Note that ro = r l\/n. For tables of the coefficients, see p. 63. This quantity r (or ro) is best regarded as merely a conventional means of recording the relative precision of different sets of observations. If r is small, it may be inferred that most errors of the " accidental" class have been eliminated; but it should be especially noted that the smallness of r gives no information in regard to "constant" or "systematic" errors. A statement like ''x is equal to 2.36 with a probable error of 0.02," is written: x = 2.36 + 0.02, and is usually understood to mean that the true value of x, as far as can be told, is just as likely to lie inside as outside the interval from 2.34 to 2.38. 122 ALGEBRA ' To test the distribution of residuals, arrange the residuals in order of magnitude, without regard to sign, and count the number, y, of residuals which are numerically less than some assigned value a; divide y by w, the total number of observations, and divide a by r, the probable error of a single observation. Do this for various values of a, and compare the results with the table on p. 63, which gives the standard distribution of residuals, as found from experience from a large number of different series of observations. In particular, the number of residuals numerically less than r should be about equal to the number numerically greater than r (if n is large). If any large discrepancy appears, the series of observations should be regarded as unsatis- factory. NOTE. The "mean square error" sometimes met with is equal to the probable error divided by 0.6745. Case 2. Several Unknown Quantities. Assume that there have been obtained by measurement or observation n different equations of the first degree involving, say, three unknown quantities, Given Equations x, y, z. There are then n simultaneous equations a\x + biy + c\z = pi in three unknowns, and if n > 3 there will be, in azx + b%y + czz = pz general, no set of values of x, y, z which will satisfy all these n equations exactly. In such a case, a n x -f- b n y + CnZ = Pn the "best" set of values, XQ, yo, ZQ, may be found by the method of least squares as follows. (The process usually involves a large amount of labor; the use of a computing machine is advisable.) First, arrange the n given equations in the form indicated, being careful not to modify any of them by multiplication or division. (Any of the coeffi- cients may of course be zero.) Next, form the three "normal equations" as follows: (1) Multiply each of the given equations by the coefficient of x in that equation, and add; the result will be the first normal equation. Normal Equations (2) Multiply each of the given equations [aa]a;o + [ab]yo + [ac]zo = [ap] by the coefficient of y in that equation, and [ba]xo -\- [bb]yo + [bc]zo = [bp] add; the result will be the second normal equa- [ca]xo + [cb]yo + [cc]zo = [cp] tion. (3) Similarly for the third. { Nota- tion: [aa] = ai 2 + a2 2 + . . . + a n 2 ; [ab] = ai&i +0262 -f- . . . +a n bn', [ap] = aipi -\-aipz + . . . +a n p n : etc.} Finally, solve the three normal equations for the three unknowns in the usual way. The quantities DI = 0,1X3 + &i2/o + C\ZQ pi, etc., are called the residuals with respect to XQ, yo, ZQ. [It can be shown that the sum of the squares of the residuals with respect to XQ, yo, ZQ is smaller than the corresponding quantity with respect to any other set of values, x'o, y'o, z'o; this relation is taken as the criterion for the "best" set of values of x, y, z.] The probable error of a single observation is 0.6745 + vz 2 + + *>n 2 , or approximately, (hi + M + . . . + hi), n(n m) where m = the number of unknown quantities (here m = 3). DETERMINANTS 123 DETERMINANTS Determinants are used chiefly in formulating theoretical results; they are seldom of use in numerical computation. Evaluation of Determinants : Of the second order: |a 2 & 2 | 0162 Of the third order: 02&2C2 = Ol & 2 c 2 &3C3 &1C1 he &3C2) 2 (6lC3 Of the fourth order: &2C2C?2 , *! v a ^a**a dz baCada dabacada 6404^ bzczdz baCadal etc. In general, to evaluate a determinant of the nth order, take the ele- ments of the first column with signs alternately plus and minus, and form the sum of the products obtained by multiplying each of these elements by its corresponding minor. The minor corresponding to any element ai is the determinant (of next lower order) obtained by striking out from the given determinant the row and column containing 01. Properties of Determinants. 1. The columns may be changed to rows and the rows to columns: 010203 a 2 6 2 c 2 036303 ClC 2 C3 2. Interchanging two columns changes the sign of the result. 3. If two columns are equal, the determinant is zero. 4. If the elements of one column are m times the elements of another column, the determinant is zero. 5. To multiply a determinant by any number m, multiply all the elements of any one column by m. 7. Solution of Simultaneous Equations by Determinants. If aix + biy + ciz = pi 01 + PI + 3i, bi ci ai&ici pibici 01&lCl| a 2 + p 2 + 0.2, bz Cz = 02&2C2 -|- Pzbzcz -f- qzbzczl 03 + Pa + qa, ba ca 03&3C3 pabaca qabacal dibiCi 01 + mbi, &i ci azbzcz = o 2 + mbz, bz Cz aabaCa 03 + mba, ba Ca aix + bzy + czz = p 2 aax + bay + caz = PS then x = Di/D, y = D 2 /Z>, where Di z = Da/D, where D PI&IC a 2 & 2 c 2 dabaca 0, pabaca aapac Da = Similarly for a larger (or smaller) number of equations. 124 ALGEBRA THE ALGEBRA OF IMAGINARY OR COMPLEX QUANTITIES In the algebra of imaginary or complex quantities, the objects on which the operations of the algebra are performed are not numbers in any ordinary sense of the word, but are best thought of as points in a plane (or as vectors drawn from a fixed origin to these points). The "complex plane" is de- termined by three fundamental points, O, U, i, arranged as in Fig. 2 and called the zero point, the unit point, and the imaginary unit point, respectively. All points on the line through O and U are called real points positive if on the right of O, negative if on the left. All the remain- ing points in the plane are called imaginary points those on the line through and i being called the pure imaginary points. The position of any point A in the plane may be de- termined by the distance from the origin O, measured in terms of OU as the unit length, and the angle

is sometimes called the amplitude or argument of the point. The notation FIG. 2. A = (3, ^120) means the point whose distance, r, is 3 times OU, and whose angle, , any point A =* x + iy can be expressed A = r (cos

), where r is real and positive (namely, the distance of A), and

i+i sin i)] [r 2 (cos 2+i sin

t) +* sin (^1+^2)]; [r(cos^ + iam Q -A = \/ e A. e \ = e> e O = lt The function e A is a periodic function with a pure imaginary period 2iri; that is, e A k ' i ir i = e A t where k is any positive integer. If A is made to move along a line parallel to the axis of reals [or axis of pure imaginaries], the corresponding point e A will move along a straight line through [or along a circle about O as center]. Properties of e lv> . The point e l(p is a point whose distance is 1 and whose angle is . It follows from the definitions above that multiplying any point A by e l has the effect of rotating the point through an angle > where r is the distance and

, then r = Vz 2 + y 2 , sin * = , cos*> = , tan 1 = rze l , then log e (x + iy) = loge r + i

+ on tO +0 - oo tO -0 -Oto- H-S/3 V3 1 1 1 V3 H-S/3 vers x covers x +0to+l +lto+0 +lto+2 +0to+l +2to+l + lto+2 +HO+O +2to+l \/2 =1.4142; H\/2 =0.7071; A/3 =1.7321; ^VV = 0.8660; W3 =0.5774; ^A/3 =1.1547 Trigonometrical Tables. The tables on pp. 46-56 give the values of the principal trigonometric functions and of their logarithms, correct to four places of decimals, the angle advancing either by tenths of a degree (p. 46) or by 10 min. (p. 52). These tables will be found adequate for most 130 TRIGONOMETRY computations in which an accuracy of 1 part in 1000 is sufficient. If much computing is to be done, it is advisable to use a separate volume of tables, containing more facilities for interpolation, and printed in larger type, such as the four-place tables of E. V. Huntington (Harvard Cooperative Society, Cambridge, Mass.), with convenient marginal tabs; the five-place tables published by Macmillan or many others; the six-place tables of Bremiker; the standard seven-place tables of Schron, Vega, or Bruhns (angles advancing by 10 sec.); or the great eight-place of Bauschinger and Peters (angles advancing at intervals of 1 sec. fromO deg. to 90 deg.). The larger tables give only the logarithms of the functions, not the natural values. To Find Any Function of a Given Angle. (Reduction to the first quadrant.) It is often required to find the functions of any angle x from a table that includes only angles between deg. and 90 deg. If x is not already between deg. and 360 deg., first "reduce to the first revolution" by simply adding or subtracting the proper multiple of 360 deg. ; [for any func- tion of (z) = the same function of (x n X 360)]. Next reduce to the first quadrant as follows: If x is between 90 and 180 180 and 270 270 and 360 Subtract 90 from x 180 from x 270 from x Then sin x = +cos (x-90) = +sec (a; -90) = -sin (x-90) *=-csc (x-90) = -cot (x-90) = -tan (x-90) = -sin (x-180) = -csc (a: -180) = -cos (x-180) = -sec (x -180) = +tan (x-180) = +cot (s-180 ) = -cos (x-270) = -sec (x -270) = +sin (x-270) = +csc (x -270) = - cot (x - 27C; = -tan (x -270) esc x COS X sec x tan x cot x vers x = l+sin (x -90) = l-cos (a; -90) = l+cos (a- 180) = l+sin (a; -180) = l-sin (z-27(x y); cos x + cos y = 2 cos y*(x + j/) cos ^(x y}\ cos x cos y = 2 sin W(x + #) sin \i(x y); sin (x + y) sin (x + y) tan & -f tan y = - ; cot x + cot j/ = cos x cos y sin x sin |/ FIG. 5. sin (x y) cot x cot y x) tan x tan y = cos x cos j/ sin x sin y sin 2 x sin 2 2/ = cos 2 y cos 2 x = sin (x + y) sin (x y); cos 2 x sin 2 y = cos 2 |/ sin 2 x = cos (x + y) cos (x y) ; sin (45 + x) = cos (45 - x) ; tan (45 + x) = cot (45 - x) ; sin (45 - x) = cos (45 + x): tan (45 - x) = cot (45 + x). In the following transformations, a and b are supposed to be positive, c = V^ 2 + b 2 , A = the positive acute angle for which tan A = a/b, and B = the positive acute angle for which tan B = b/a: a.cos x + b sin x = c sin (A + x) = c cos (B x) ; a cos x 6 sin x = c sin (A x) = c cos (B + x). Functions of Multiple Angles and Half Angles. sin 2x = 2 sin x cos x; sin x = 2 sin MX cos ^x; cos 2x = cos 2 x sin 2 x = 1 2 sin 2 x = 2 cos 2 x 1 ; 2 tan x cot 2 x 1 tan2x 1 - tan 2 x' cot 2x 2 cot x 3 tan x tan 3 x sin 3x = 3 sin x 4sm 3 x; tan 3x = cos 3x = 4 cos 3 x 3 cosx; 1-3 tan 2 x 132 TRIGONOMETRY sin (n*) = n sin x cos w ~ 1 x (n)a sin 3 * cos n ~ 3 * + (n)s sin 5 a; cos n ~ 6 cos (n*) = cos n a; (n)z sin 2 a; cos n - 2 * + (n) 4 sin 4 a; cos n ~ 4 a where (n) 2 , (n) 8 , . . . are the binomial coefficients (see p. 39). sin M x = \A$(1 cos a;); 1 cos x =2 sin 2 MX; cos MX = + V^(l + cos *); 1 -f- cos* = 2 cos 2 ,_ cos * sin * 1 cos * tan . _ cos * sin * /* \ /I 4- sin -r tan (a +45 C sin * Here the+ or sign is to be used according to the sign of the left-hand side of the equation. Relations Between Three Angles Whose Sum is 180. , sin A + sin B + sin C = 4 cos MA cos MB cos MC; cos A + cos B + cos C = 4 sin MA sin MB sin MC + 1 ; sin A -\- sin B sin C = 4 sin MA sin J&B cos MC; cos A -j- cos B cos C = 4 cos ^ A cos MB sin }C 1 ; sin 2 A + sin 2 J5 + sin 2 C = 2 cos A cos cos C + 2; sin 2 A + sin 2 B sin 2 C = 2 sin A sin B cos C; tan A + tan B + tan C = tan A tan B tan (7; cot^A+ cot MB + cot ^(7 = cot MA cot 1B cot MC; cot A cot B + cot A cot (7 + cot B cot (7 = 1; sin 2A + sin 2B + sin 2(7 = 4 sin A sin B sin C; sin 2A -j- sin 2B sin 2C =4 cos A cos B sin C. Inverse Trigonometric Functions. The notation sin" 1 * (read: anti- sine of *, or inverse sine of *; sometimes written arc sin *) means the prin- cipal angle whose sine is *. Similarly for cos" 1 *, tan" 1 *, etc. (The prin- cipal angle means an angle between 90 and +90 in case of sin" 1 and tan" 1 , and between and 180 in the case of cos" 1 .) For graphs, see p. 174. SOLUTION OF PLANE TRIANGLES The "parts" of a plane triangle are its three sides, a, 6, c, and its three angles A, B, C (A being opposite a, B opposite b, C opposite c, and A + B + (7 = 180). A triangle is, in general, determined by any three parts (not all angles). To "solve" a triangle means to find the unknown parts from the known. The fundamental formula? are: Law of sines : - = . Law of cosines : c 2 = a 2 + b 2 2ab cos C. b smB Right Triangles. Use the definitions of the trigonom- etric functions, selecting for each unknown part a relation which connects that unknown with known quantities; then solve the resulting equations. Thus, in Fig. 6, if C = 90, then A + B - 90, c 2 = a 2 + 6 2 , sin A = a/c, cos A = 6/c, tan A = a/b, cot A = b/a. If A is very small, use tan MA = \/(c 6)/(c + 6). Oblique Triangles. There are four cases. It is highly desirable in all these cases to draw a sketch of the triangle approximately to scale before commencing the computation, so that any large numerical error may be readily detected. Case 1. GIVEN Two ANGLES (provided their sum is < 180 deg.), AND ONE SOLUTION OF PLANE AND SPHERICAL TRIANGLES 133 SIDE (say o, Fig. 7). The third angle is known, since A To find the remaining sides, use b a sin B a sin C + B + C A = 180. sin A sin A Or, drop a perpendicular from either B or C on the opposite side, and solve by right triangles. -p IQ 7 Check: c cos B + 6 cos C = a. Case 2. GIVEN Two SIDES (say a and 6), AND THE INCLUDED ANGLE (C) ; and suppose a > 6. Fig. 8. First Method: Find c from c 2 = a 2 + 6 2 2ab cos C [or c 2 = (o 6) 2 + 2a& vers C]; then find the smaller angle, 5, from sin B = (6/c) sin C; and finally, find A from A = 180 (B + C). Check: a cos B + b cos A = c. Second Method: Find (A B) from the law of tangents: tad #(A - J3) = [(a - 6) /(a + 6)] cot &C, and tf(A + B) from #(A + B) = 90 C/2; hence A = H(A + ) + #(A -5) and B = y*(A + B) -\ 1, there is no solution. If sin C = 1, C = 90 and the triangle is a right triangle. If sin C< 1, this determines two angles C, namely, an acute angle Ci, and an obtuse angle Cj = 180 Ci. Then Ci will yield a solution when and only when 134 TRIGONOMETRY Ci +B < 180 (see Case 1); and similarly C 2 will yield a solution when and only when Cz + B < 180 (see Case 1). Other Properties of Triangles. (See also p. 99 and p. 105.) Area = tyab sin C = \/s(s a) (s b)(s c) = rs, where s = 3,i(a + b -f- c), and r =radius of inscribed circle = \/(s a)(s 6)(s c)/s. Radius of circumscribed circle = R, where 2R = a/sin A = 6 /sin B = c/sin C; r = 4R sin 4 sin ^ sin ? = ^-. 222 4/ts The length of the bisector of the angle C is - c) Vab[(a + b) 2 - c 2 ] a +b a + 6 The median from C to the middle point of c is m = }S\/2(a 2 + 6 2 ) c 2 . SOLUTION OF SPHERICAL TRIANGLES For the occasional solution of a spherical triangle the following formulae will be sufficient. For a detailed discussion, see any text-book on spherical trigonometry. Let a, b, c be the eides-of the spherical triangle, that is, portions of arcs of great circles of the sphere; and let A, B, C be the angles of the triangle, that is, the angles made by tangents drawn to the sides at their points of intersection on the sphere. The sum of the angles will always be greater than two right angles, and may be nearly six right angles. The angle E = A + B + C 180 is called the spherical excess of the triangle. (See also p. 100.) sin a sin b sin 6 sin c sin c sin a sin A sin B ' sin B sin C 1 sin C sin A cos a = cos 6 cos c + sin b sin c cos A, with similar formulae for cos b and cos c. cos A = cos B cos C + sin B sin C cos a, with similar formulae for cos B and cos C. In the special case of a right spherical triangle, in which C = 90, cos A cos B cos c = cos a cos o =cotA cotB; cos a = - ; cos o = -; sin B sin A sin a tan b tan a sin A = ; cos A = ; tan A = sin c tan c sin o The area of a spherical triangle _ spherical excess area of a great circle 180. HYPERBOLIC FUNCTIONS 135 HYPERBOLIC FUNCTIONS The hyperbolic sine, hyperbolic cosine, etc., of any number x, are functions of x which are closely related to the exponential e x , and which have formal properties very similar to those of the trigonometric functions, sine, cosine, etc. Their definitions and fundamental properties are as follows (see also p. 127; graphs, p. 175; table, p. 60; series, p. 161): sinh x = }$(e x e~ x ); cosh a; = li(e x + e~ x '); tanh a; = sinh a; /cosh Z; csch x = 1/sinh x; sech x = 1/cosh x; coth x = 1/tanh x; cosh 2 x sinh 2 x =1; 1 tanh 2 x = sech 2 x; 1 coth 2 x = csch 2 x; sinh ( x) = sinh x\ cosh ( x) = cosh x; tanh ( x) = tanh x\ sinh {x !/) = sinh x cosh y cosh x sinh y; cosh (x + y) = cosh x cosh y sinh x sinh y; tanh (a; !/) = (tanh x tanh !/)/(! tanh x tanh y); sinh 2x = 2 sinh x cosh x; cosh 2x = cosh 2 - a; + sinh 2 x ; tanh 2x = (2 tanh x) /(I + tanh 2 x) ; sinh^z =\As (cosh a; 1); cosh ftx = V^cosh a; + 1); tanh MX = (cosh x l)/(sinh x) = (sinh o;)/(cosh x + 1). The inverse hyperbolic sine of y, denoted by sinh"" 1 !/, is the number whose hyperbolic sine is y; that is, the notation x = sinh" 1 !/ means sinh x = y. Similarly for cosh- 1 !/, tanh- 1 !/, etc. These functions are closely related to the logarithmic function, and are especially valuable in the integral calculus. For graphs, see p. 175. sinh-^/a) = log e (y + Vy + o 2 ) log e a; cosh- l (y/a) = log e (y + VV 2 a 2 ) log e a; y f_l-7y 7/ 1J -\- d tanh- 1 - = ^log e -^-^; coth- 1 - = ^log, ^ ! a a y a y a The anti-gudermannian of an angle w, denoted by gd"" 1 ^, is a number defined by gd~ ] w = log e tan ( l Air + tfu) = J'sec u du. When u is small, gd~ l u = u + y*u* ANALYTICAL GEOMETRY THE POINT AND THE STRAIGHT LINE Rectangular Co-ordinates (Fig. 1). Let Pi = (xi, yi), P 2 = (22, 1/2). Then, distance PiP2 = V(^i ^) 2 + (y\ 2/2)*; slope of PiP 2 = m tan u = (Zft 2/i)/(2 xi); co-ordinates of mid-point are x = li(xi + xz), y = Yt(yi + 2/2); co-ordinates of point (l/w)th of the way from Pi to Pa are x = xi + (1AO(Z2 - si), / = 2/1 + (l/n)(2/ 2 - 3/1). Let mi, mi be the slopes of two lines; then, if the lines are parallel, mi = m*; if the lines are perpendicular to each other, mi = 1/mz. Equations of a Straight Line. 1. Intercept Form (Fig. 2) : \- - = 1. (a, b = intercepts of the line on a o the axes.) 2. Slope Form (Fig. 3) : y = mx + b. (m = tan u = slope; 6 = inter- cept on the 2/-axis; see also Fig. 2, p. 174.) 3. Normal Form (Fig. 4) : x cos v -f y sin v = p. (p = perpendicular from origin to line; v = angle p makes with the x-axis.) 4. Parallel-intercept Form (Fig. 5) : - - = - (6, c = intercepts on C ~"~ O nJ two parallels at distance k apart.) FIG. 1. FIG. 2. FIG. 3. 5. General Form: Ax + By + C = 0. [Here a = - C/A, b = - C/B, m = A/B, cos v = A/R, sin v = B/R, p = - C/R, where R = \/4 2 + .B a (sign to be so chosen that p is positive).] 6. Line Through (xi, yi) with Slope m: y yi = m(x xi). 7. Line Through (xi, yi) and (xz, yi): y yi = - - 1 (x an). Xz zi 8. Line Parallel to a;- axis: x = a; to y-axis: y = b. Angles and Distances. If u *= angle between two lines whose slopes are mi, mz, then mz mi If parallel, mi = mz. 1 + mjmi If perpendicular, mim2 = 1. If u = angle between the lines Ax + By + C = and A'x + J5'i/ + C' = 0, then A A' + BE' If parallel, A /A' = B/B'. COS M = - ' + \/(A 2 + 2 ) (A /2 +5' 2 ) If perpendicular, A A' -f 5B' = 0. The equations of the bisectors of the angles between the two lines just mentioned are THE POINT AND THE STRAIGHT LINE; THE CIRCLE 137 The equation of a line through (xi, y\) and meeting a given line y = mx + b at an angle u, is ra + tan u y 2/i = ; (z zO- 1 ra tan w The 'distance from (XQ, y$) to the line Ax + By + C = is where the vertical bars mean "the absolute value of." The distance from (XQ, j/o) to a line which passes through (xi, y\) and makes an angle u with the z-axis, is D = (XQ xi) sin u (2/0 2/0 cos u. Polar Co-ordinates (Fig. 6). Let (x, y) be the rec- tangular and (r, 0) the polar co-ordinates of a given point P. Then x = r ccys 0; y = r sin 6; x* + y z = r 2 . Transformation of Co-ordinates. If origin is moved to point (XQ, 2/0), the new axes being parallel to the old, fiQ. 6. x XQ + x', y = yo + y'> If axes are turned through the angle u, without change of origin, x = x' cos u y f sin u, y = x' sin u + y' cos u. THE CIRCLE (See also pp. 99, 103-105, 106) Equation of Circle with center (a,6) and radiu a r: (x - a) 2 + (y - 6)2 = r 2 . If center is at the origin, the equation becomes x* + j/ 2 = r 2 . If circle goes through the origin and center is on the z-axis at point (r, 0), equation becomes z 2 + y 2 = 2rx. The general equation of a circle is x 2 + 2/ 2 + Dx + Ey +F = 0; it has center at ( -D/2, -E/2), and radius =\/(-D/2) 2 + (E/2) 2 F (which may be real, null, or imaginary). The equation of the radical axis of two circles, x 2 + y 2 + Dx + Ey + F = and x 2 + y 2 + .D'z + JE's/ + F 1 =0, is (Z> - D')x + (E E'}y + (F F') = 0: The tangents drawn to two circles from any point of their radical axis are of equal length. If the circles intersect, the radical axis passes through their points of intersection (see p. 100). The equation of the tangent to x 2 + y 2 = r 2 at (xi, 2/1) is xix + y\y = r 2 . The tangent tp x 2 + y 2 + Dx + Ey + F = at (xi, y\) is xix + yiy + yzD(x + a*) + ftE(y +2/1) + F = 0. The line y = mx + b will be tangent to the circle x 2 -}- y* =* r z if b = a\/l + m 2 . Equations of Circle in Parametric Form. It is sometimes convenient to express the co-ordinates x and y of the moving point P (Fig. 7) in terms of an auxiliary variable, called a parameter. Thus, if the parameter be taken as the angle u which the radius OP makes with the z-axis, then the equations of the circle in parametric form will be a; = acosu;y = asinu. For every value of the parameter w, there corresponds a point (x, y) on the circle. The ordinary equation x 2 + j/ 2 = a 2 can be obtained from the parametric equations by eliminating u. FIG. 7. 138 ANALYTICAL GEOMETRY THE PARABOLA The parabola (see also p. 107) is the locus of a point which moves so that its distance from a fixed line (called the directrix) is always equal to its distance from a fixed point F (called the focus) . See Fig. 8. The point half-way from iocua to directrix ia the vertex, O, The line through the focus, perpen- dicular to the directrix, is the principal axis. The breadth of the curve at the focus is called the latus rectum, or parameter, = 2p, where p is the distance from focus to directrix. (Compare also Fig. 3, p. 174..) H s < x *\PS ip^ V I /YlS / 'V X pi v Directrix P T \ Fic F M p N u 8. A/ FIG. 9. FIG. 10. Any section of a right circular cone made by a plane parallel to a tangent plane of the cone will be a parabola. Equation of Parabola, origin at vertex (Fig. 8) : j/ 2 = 2px. Polar Equation of Parabola, referred to F as origin and Fx as axis (Fig. 9): r = p/(l - cos 6). Equation Referred to the Tangents at the ends of the latus rectum a? axes (Fig. 10) : x^ + y^ = o^, where a = p\/2. \ FIG. 11. FIG. 12. FIG. 13. The Equation of Tangent to y 2 = 2px at (xi,yi): y\y = p(x + xi). line y = mx + b will be tangent to y* = 2px if 6 = p/(2m). The tangent PT at any point P bisects the angle between PF and PH (Fig. 8). A ray of light from F, reflected at P, will move off parallel to the principal axis. The subtangent, TM , ia bisected at O. The subnormal, M N, ia constant, and equal to p. The locus of the foot of the perpendicular from the focus on a moving tangent ia the tangent at the vertex (Fig. 11). The locus of the point of intersection of perpendicular tangents is the directrix (Fig. 12). The Iocua of the mid-points of a set of parallel chords whose slope is m is a straight line parallel to the principal axis at a distance THE PARABOLA 139 and is called a diameter (Fig. 13). If M is the mid-point of a chord PQ, and if T is the point of intersection of the tangents atP and Q, then TM is parallel to the principal axis, and is bisected by the curve (Fig. 13). To Construct a Tangent to a Given Parabola. (1) At a given point of contact, P (Fig. 14): Find T so that OT = OM, or FT = FP. Then TP is the tangent at P. Or, make MAT = p = 2(OF); ihenPN is the normal atP. (2) From a given external point, Q (Fig. 15) : With Q as center and radius QF draw circle cutting the directrix in H ; draw HP parallel to principal axis; then P is required point of contact. As check, note that QP is the perpen- dicular bisector of FH. M N FIG. 14. FIG. 15. FIG. 16. To Construct a Parabola. 1. GIVEN ANT Two POINTS, P AND Q, THE TANGENT PT AT ONE OP THEM, AND THE DIRECTION OF THE PRINCIPAL Axis OX. In Fig. 16, let K be a variable point on a line through Q parallel to OX. Draw KR parallel to PT (meeting PQ in R), and draw RS parallel to OX (meeting PK in S) ; then S is a point of the curve. NOTE. A line through P parallel to the principal axis bisects all chords parallel to the tangent PT. 2. GIVEN THE VERTEX O AND Focus F. (a) In Fig. 17 draw Oy perpen- dicular to OF, and slide the vertex of a right angle along Oy so that one side always passes through F; then the other side will always be a tangent to the parabola. O , F FIG. 17. FIG., 18. (6) Take a piece of paper (Fig. 18) with a straight edge, d, and mark a point F near the edge. Let K be a variable point of the edge, and fold the paper so that K coincides with F. The crease will be a tangent to the parabola which has focus F and directrix d. (c) In Fig. 19, let M be a variable point of the principal axis, and lay off MN = 2(OF) p. WithF as center and radius FN draw a circle, cutting the perpendicular at M in P. Then P is a point of the curve, and PT and PN are the tangent and normal at P. 3. GIVEN Two TANGENTS AND THEIR POINTS OF CONTACT, P AND Q (Fig. 20) . Divide TP and QT into any number of equal parts (here 4) . Then the lines 11, 22, 33, . . . will be tangents to the parabola. This method is especially advantageous in drawing rather flat arcs. 140 ANALYTICAL GEOMETRY The Radius of Curvature of y* = 2px at a point P = (x,y) is R = (p + 2z)^/\/p, or R = p/sin 3 v, where v = the angle which the tangent at P makes withPF (Fig. 21). At the vertex, R = p. To construct the radius of curvature at any point P, lay off PR = 2(PF) parallel to the principal axis, and draw RC perpendicular to the axis, meeting the normal, PN, in C. Then Cis the center of curvature for the point P, and a circle about C with radius CP will coincide closely with the parabola in the neighborhood of P. FIG. 20. FIG. 21. THE ELLIPSE The ellipse (see also p. 107) has two foci, F and F' (Fig. 22) , and two direc- trices, DH and D'H'. If P is any point of the curve.PF +PF' is constant, =2a; and PF/PH (or PF'/PH') is also constant, -e, where e is the eccentricity (e 45^ JT IG 45. of curvature at any other point P (Fig. 46) , draw the normal at P (by bisecting the angle between PF and PF') and let it meet the major axis in N. At N draw a perpendicular toPN meet- ing PF in H . At H draw a perpendicular to PH meeting PN in C. Then C is the center of curvature for the point P, and a circle about C with radius CP will coincide closely with the ellipse in the neighborhood of P. [Note. If the circle of curvature meets the ellipse in Q, then the tangent at P and the line PQ are equally inclined to the axis.] THE HYPERBOLA The hyperbola (see also p. 107) has two foci, F and F', at distances ae from the center, and two directrices, DH and D'H', at distances a/e from FIG. 47. FIG the center (Fig. 47). If P is any point of the curve, \PF PF'\ is constant, = 2a; &ndPF/PH (orPF'/PH') is also constant, = e (called the eccentricity), where e > 1. Either of these properties may betaken as the definition of the THE HYPERBOLA 145 curve. The curve has two branches which approach more and more nearly two straight lines called the asymptotes. Each asymptote makes with the principal axis an angle whose tangent is b/o. The relations between e, a, and b are shown in Fig. 48: b 2 = o 2 (e 2 1), ae = Va 2 + b 2 , e 2 = 1 + (b/a) 2 . The semi-latus rectum, or ordinate at the focus, is p = o(e 2 1) =b 2 /a. Any section of a right circular cone made by a plane which cuts both nappes of the cone will be a hyperbola. (Compare also Fig. 3, p. 174.) Equation of the Hyperbola, center as origin: - r, = 1. or y a* b* If P = (x,y) is on the right-hand branch, PF = ex a, PF' = ex+a. If P is on the left-hand branch, PF = -ex +a, PF' = -ex -a. Equations of Hyperbola in Parametric Form. (1) x = a cosh u, y b sinh u. (For tables of hyperbolic functions, see pp. 60 and 61.) Here u may be interpreted as A /a 2 , where A is the area shaded in Fig. 49. FIG. 49. FIG. 50. (2) x = a sec v, y = b tan v, where v is an auxiliary angle of no special geometric interest. Polar Equation, referred to focus as origin, axes as in Fig. 50: r = p/(l e cos 6). Equation of the Tangent at (zi,2/i): b*xix a*yiy =o 2 b 2 . The line y = mx + k will be a tangent if k = VVm 2 6 2 . Thetan- FIG. 51. FIG. 52. FIG. 53. \ gent at any point P (Fig. 51) bisects the angle between PF andPF'. The locus of the foot of the perpendicular from the focus on a moving tangent is the circle on the principal axis as diameter (Fig. 52). The locus of the point of intersection of perpendicular tangents is a circle with radius \/fl 2 b 2 , which will be imaginary if 6 > a (Fig. 53). 10 146 ANALYTICAL GEOMETRY Properties of the Asymptotes. (Fig. 54. ) If P is any point of the curve, the product of the perpendicular distances from P to the two asymptotes is con- stant, = o 2 6 2 /(a 2 + 6 2 ). Also, the product of the oblique distances (the dis- tance to each asymptote being measured parallel to the other) is constant, and equal to }4(o 2 + b z ). If a line cuts the hyperbola and its asymptotes, the parts of the line intercepted between the curve and the asymptotes are equal. The part of a tangent intercepted between the asymptotes is bisected by the point of contact. The triangle bounded by the asymptotes and a variable tangent is of constant area, = ab. If a line through Q perpendicular to the principal axis meets the asymptotes in R and S (see Fig. 54), then QR X QS b*. If a line through Q parallel to the principal axis meets the asymptotes in U and V, then QU X QV = a 2 . FIG. 54. FIG. 55. Conjugate Hyperbolas are two hyperbolas having the same asymptotes with semi-axes interchanged (Fig. 55). The equation of the hyperbola conju- x* y* x* y 2 gate to - 2 -- 2 = 1, is - 2 -- 1. Conjugate Diameters are lines through the center, each of which bisects all the chords parallel to the other a chord which does not meet the given hyperbola being understood to be terminated by the conjugate hyperbola (Fig. 65). If mi and m* are the slopes, then rmmz = 6 2 /a 2 . Each asymptote, regarded as a diameter, is its own conjugate. If a parallelogram is formed by tangents drawn parallel to a pair of conjugate diameters, its vertices will lie on the asymptotes, and its area will be constant = 4a&. If a', b' are conjugate semi-diameters, and w the angle between them, then a /2 b' 2 = a 2 6 2 , and a'b' = ab/sin w. Equilateral Hyperbola (a =6). Equation referred to principal axes (Fig. 56) : x* y* = a 2 . NOTE, p = a. Equation referred to asymptotes as axes (Fig. 57) : xy = o 2 /2. (See also Fig. 3, p. 174.) Asymptotes are perpendicular. Eccentricity = \/2. Any diameter is equal in length to its conjugate diameter. y Fio. 66. FIG. 67. THE CATENARY 147 To Construct a Tangent at any given point P of a hyperbola. In Fig. 58, draw PA and PS parallel to the asymptotes, and take OS = ?(OA) and OT = 2(OB). Then ST is the tangent at P. FIG. 58. To Construct a Hyperbola^ given the asymptotes and any point P. (1) In Fig. 59 let TPT' bea variable line throughP, andlayoff T'P f = TP; then P' is a point of the curve. (2) In Fig. 60, draw PA and PB parallel to the asymptotes. Lay off OA' = n(OA) and OB' = (\/ri)(OB}, where n is any number; and throughA' and B f draw parallels to the axes; these will meet in a point P' of the curve. FIG. 59. FIG. 61. (3) (Fig. 61.) Take any point K in the ordinate PM, and draw OK meeting the line through P parallel to the z-axis in R. Draw a parallel to the x-axis through K and a parallel to the y-axia through R, meeting in Q. Then Q is a point of the curve. THE CATENARY The catenary is the curvein which aflexible chain or cord of uniform density will hang when supported by the two ends. Let w = weight of the chain per unit length ; T = the tension at any point P; and Th,T v = the horizontal and vertical components of T. The horizontal com- ponent Th is the same at all points of the curve. The length a = Th/w is called the parameter of the catenary, or the distance from the lowest point O to the directrix DQ (Fig. 62). When a is very large, the curve is very flat. For methods of finding o in any given case, see problems 1-6 below. The rectangular equation, referred to the lowest point as origin, is y a [cosh (x/a) 1]. (For table of hyperbolic functions, see p. 60.) In case of FIG. 62. 148 ANALYTICAL GEOMETRY x 2 very flat arcs (a large), y = - . . . ; s = x + ^ + approximately, so that in such a case the catenary closely resembles a parabola. If the perpendicular from O to the tangent at P meets the directrix in Q, then DQ = arc OP = s andOQ = y + o. The radius of curvature atP is R = (y +o) 2 /o, which is equal in length to the portion of the normal inter- cepted between P and the directrix. Problems on the Catenary (Fig. 62). When any two of the four quantities x, y, s, T/w are known, the remaining two, and also the para- meter a, can be found, as follows: ( 1) GIVEN x AND y. Compute y/x, and find from Table 1 the value of the auxiliary variable z. Then compute a = x/z, s = a sinh z, and T wa cosh z. Or, having z, find s/x and wx/T by using Tables 3 and 2 inversely, and hence (since x is known) compute s and T/w without the use of o. TABLE 1. GIVING z WHEN y/x is KNOWN. THEN a = x/z y/x 1 2 3 4 5 6 7 8 9 00 0.0000 0.0200 0.0400 0.0600 0.0800 0.0999 n .1199 0.1398 0.1597 0.1795 01 0.1993 0.2191 0.2389 0.2586 0.2782 0.2978 .3173 0.3368 0.3562 0.3756 02 0.3948 0.4140 0.4332 0.4522 0.4712 0.4901 r .5089 0.5276 0.5463 0.5648 0.3 0.5833 0.6016 0.6199 0.6381 0.6561 0.6741 n .6919 0.7097 0.7274 0.7449 4 0.7623 0.7797 0.7969 0.8140 0.8311 0.8480 n .8647 0.8814 0.8980 0.9145 05 0.9308 0.9471 0.9632 0.9792 0.9951 1.0109 i .0266 1.0422 1 .0576 1.0730 0.6 1.0883 1.1034 1.1184 1.1334 1.1482 1.1629 i .1775 1.1920 1.2064 1.2207 NOTE. y/x - (cosh z DA- (2) GIVEN x AND T/w. Compute wx/T, and find from Table 2 the value of the auxiliary variable z. Then compute a = x/z, y = a. (cosh z l)and a = a sinh z. Or, having z, find y/x and s/x by using Tables 1 and 3 inversely, and hence (since x is known) compute y and s without the use of a. TABLE 2. GIVING z WHEN wx/T is KNOWN. THEN a = x/z wx/T 1 2 3 4 5 6 7 8 9 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.0000 0.1005 0.2042 0.3150 0.4392 0.5894 0.8053 0.0100 0.1107 0.2149 0.3267 0.4528 0.6068 0.8357 0.0200 0.1209 0.2256 0.3385 0.4666 0.6249 0.8695 0.0300 0.1311 0.2365 0.3505 0.4806 0.6436 0.9082 0400 1414 2474 3626 4950 6632 9541 0.0501 0.1517 0.2584 0.3749 0.5097 0.6836 1.0132 0.0601 0.1621 0.2695 0.3874 0.5248 0.7051 1.1110 0.0702 0.1725 0.2807 0.4000 0.5403 0.7277 0.0803 0.1830 0.2920 0.4129 0.5562 0.7517 00904 0.1936 0.3035 0.4259 0.5726 0.7775 NOTE. wx/T = z/cosh z. For every value of wx/T there are two values of z, one less than 1.200 and one greater than 1.200. Only the smaller of these values is tabulated. (3) GIVEN x AND s. Compute s/x, and find from Table 3 the value of the auxiliary variable z. Then compute a = x/z, y a (cosh z l),and T = wa cosh z. Or, having z, find y/x and wx/T by using Tables 1 and 2 inversely, and hence (since x is known) compute y and T/w without the use of a. THE CATENARY 149 TABLE 3. GIVING z WHEN s/x is KNOWN. THEN a = x/z /* 1 2 3 4 5 6 7 8 9 1.000 0245 0.0346 0424 0.0490 0.0548 0.0600 0.0648 0.0693 0.0735 1 6 ! 0774 0.0812 0.0848 0.0883 0.0916 0948 0.0980 0.1010 0.1039 0.1067 2 0.1095 0.1122 0.1149 0.1174 0.1200 1224 0.1249 0.1272 0.1296 0.1319 3 0.1341 0.1363 0.1385 0.1407 0.1428 1448 0.1469 0.1489 0.1509 0.1529 4 0.1548 0.1567 0.1586 0.1605 0.1623 1642 0.1660 0.1678 0.1696 0.1713 1.005 0.1731 0.1748 0.1765 0.1782 0.1799 o 1815 0.1831 0.1848 0.1864 C.1880 6 0.1896 0.1911 0.1927 0.1942 0.1958 1973 0.1988 0.2003 0.2018 0.2033 7 0.2047 0.2062 0.2076 0.2091 0.2105 2119 0.2133 0.2147 0.2161 0.2175 8 0.2188 0.2202 0.2215 0.2229 0.2242 2255 0.2269 0.2282 0.2295 2308 9 0.2321 0.2334 0.2346 0.2359 0.2372 2384 0.2397 0.2409 0.2421 0.2434 1.01 0.2446 0.2565 0.2678 0.2787 0.2892 0.2993 0.3091 0.3186 0.3278 3367 2 0.3454 0.3539 0.3621 0.3702 0.3781 3859 0.3934 0.4009 0.4082 U.4153 3 0.4224 0.4293 0.4361 0.4428 0.4494 4559 0.4623 0.4686 0.4748 0.4809 4- 0.4870 0.4930 0.4989 0.5047 0.5105 5162 0.5218 0.5274 0.5329 0.5383 1.05 0.5437 0.5490 0.5543 0.5595 0.5647 5698 0.5749 0.5799 0.5849 0.5898 6 0.5947 0.59% 0.6044 0.6091 0.6139 6186 0.6232 0.6278 0.6324 0.6369 7 0.6414 0.6459 0.6504 0.6548 0.6591 6635 0.6678 0.6721 0.6763 0.6806 8 0.6848 0.6889 0.6931 0.6972 0.7013 7053 0.7094 0.7134 0.7174 0.7213 9 0.7253 0.7292 0.7331 0.7369 0.7408 7446 0.7484 0.7522 0.7559 0.7597 1.10 0.7634 NOTE: s/x = sinh z/z (4) GIVEN y AND a. Then S + l *:(?-) tanh- 1 | -I i (5) GIVEN y AND T/w. Then a = y, x w y I cosh' T/w (T/w) - y s = V2y(T/w) - y*. Or, if y/(T/w) is small, 7 wi ' 12 ~T x \ wy , - = g -y , approximately, (6) GIVEN s AND T/w. Then a; =- A 1 - ( Given the Length 2L of a Chain Supported at Two Points A and B not in the Same Level, to find a. (See Fig. 63; b and c are supposed known.) Let ( \/I/ 2 b 2 ) /c = s/x; enter Table 3 with this value of s/x, and find the corresponding value of the auxiliary variable z. Then a = c/z. 150 ANALYTICAL GEOMETRY NOTE. The co-ordinates of the mid-point M of AB (see Fig. 63) are XQ = a tanh" 1 (b/L), y = (L/tanh z) a, so tha't the position of the lowest point is determined. Correction for Sag in Chaining TTphill (Fig. 64). Let I = length of tape (corrected for stretch and temperature), w = weight per unit length of tape, A = angle between the chord AB and the horizontal. FIG. 63. FIG. 64. If the tension P at the upper end is known, compute wl/P and find k from Table 4. If the tension Q at the lower end is known, compute wl/Q and find k from Table 5. In either case, chord AB = l kl. TABLE 4. GIVING k TABLE 5. GIVING k wl A=0 10 20 30 40 50 60 70 A =0 10 20 30 40 50 60 70 .00000 000 000 000 000 000 000 000 000 002 002 001 001 001 001 000 000 000 004 004 003 003 002 002 001 000 000 007 006 006 005 004 003 002 001 000 Oil 010 009 008 006 004 003 001 000 .00015 015 013 012 009 006 004 002 000 020 020 018 016 012 009 005 003 001 027 026 024 021 016 012 007 003 001 034 033 031 026 021 015 009 004 001 042 041 038 033 026 019 Oil 005 001 .00051 050 046 040 032 023 014 007 002 060 060 055 048 038 027 017 008 002 070 070 065 057 045 032 020 009 002 082 081 076 066 053 038 023 Oil 003 094 094 087 076 061 044 027 013 003 00107 107 100 087 070 050 031 015 004 ' 121 121 113 099 079 057 035 017 004 136 136 128 112 090 065 040 019 005 151 152 143 125 101 073 045 021 006 168 168 159 140 113 082 050 024 006 .00000 000 000 000 000 000 000 000 000 002 002 001 001 001 001 000 000 000 004 004 003 003 002 001 001 000 000 007 006 006 005 004 003 002 001 000 Oil 010 009 008 006 004 002 001 000 .00015 014 013 Oil 008 006 004 002 000 020 020 018 015 Oil 008 005 002 001 027 026 023 019 015 Oil 006 003 001 034 032 029 024 019 013 008 004 001 042 040 036 030 023 016 010 004 001 .00051 048 043 036 028 019 Oil 005 Oof 060 057 051 043 033 023 014 006 002 070 067 060 050 038 026 016 007 002 082 078 069 057 044 030 018 008 002 094 089 079 066 050 035 021 010 002 .00107 101 090 074 057 039 022 01 1 003 121 114 101 084 064 044 026 012 003 136 128 113 092 071 049 029 013 003 151 142 125 103 079 054 032 015 004 168 157 138 114 087 060 035 016 004 NOTE, k = 1 - {[l-\/l - 2m sin u + given by sin A]}, where m = wl/P and u is [1 \/l 2m sin u + m 2 ] secw = [sinh -1 (tanw) sinh -1 (t&nu m sec w)]tan A. Also, Q = P wl (1 k) sin A, where k is the value in Table 4 corresponding to the given values of P and A. Correction for Stretch m Chaining Uphill. Let L = unstretched length of tape at working temperature, w = weight per unit length of tape, A = angle OTHER USEFUL CURVES 151 between chord AB and the horizontal, F = area of cross-section, E = Young's modulus of elasticity (for steel, E = 29,000,OOQ Ib. per sq. in.), I = stretched length (along curve). If the tension P at the upper end is known, compute wL/P and find m from Table 6. Then I = L + (LP/FE) (1 * m). If the tension Q at the lower end is known, compute wL/Q and find nfrom Table 7. Then I = L + (LQ/FE) (1 + n) . TABLE 6.' GIVING m TABLE 7. GIVING n 'L ?- 4 oT 10 20 30 40 50 60 70 80 90 wL ~Q A= 10 20 30 40 50 60 70 80 90 .00 .10 .20 .000 .000 .000 .000 .000 .000 .000 .000 .000 .000 .001 .010.018.026.033.039.044.047.049.050 .003 .021 .038 .053 .067 .078 .088 .094 .099. 100 .00 .10 .20 .000.000.000.000.000.000.000.000 000 .008.016.024.032.038.043.047.049.050 .014 .03 1 .047 .062 .075 .086 .094 .099 . 1 00 OTHER USEFUL CURVES The Cycloid is traced by a point on the circumference of a circle which rolls without slipping along a straight line. Equations of cycloid, in parametric form (axes as in Fig. 65) \}x = a (rad u sin w), y = a(l cos w), where a is FIG. 65. FIG. 66. the radius of the rolling circle, and rad u is the radian measure of the angle u through which it has rolled. The tangent and normal at any point pass through the highest and lowest points of the corresponding position of the generating circle. The radius of curvature at any point P is PC = 4a sin(w/2) .= 2\/2ay = twice thelength of the normal, PJV. Theevolute, or I ocus of centers of curvature, is an equal cycloid. To construct a cycloid (Fig. 66), divide the semi-circumference of the gen- erating circle into n equal parts (here 4) and lay off these arcs along the base (from O to 4'). Describe arcs with centers at 1', 2', . . . and radii equal to the chords Ol, O2, . . . , and sketch the cycloid as a curve tangent to ail of these arcs. Or, on hori- zontal lines through 1,2,. . . lay off dis- tances equal to Ol', 02', etc.; the points thus reached will lie on the cycloid. The area of one arch = 37ra 2 , length of arc of one arch = 8a. Area bounded by the ordinate of the point P corresponding to any value of u is a 2 ($$ rad u 2 sin u + J4 sin 2w) = % ax ft y\/(2a y)y. Length of arc OP = 4a (1 - cos # w) = 4a - 2V / 2a(2a - y). FIG. 67. 152 ANALYTICAL GEOMETRY The Trochoid is a more general curve, traced by any point on a radius of the rolling circle, at distance b from the center (Fig. 67). It is a prolate trochoid if 6 < a, and a curtate or looped trochoid if 6 > a. The equations in either case are x = a rad u b sin u, y = a b cos w. The Epicycloid (or Hypocycloid) is a curve generated by a point on the circumference of a circle of radius a which rolls without slipping on the outside (or inside) of a fixed circle of radius c. For the equations, put 6 = a in the equations of the epi- (or hypo-) trochoid, below. The normal at any point P passes through the point of contact N of the corresponding position of the rolling circle. To construct the curve (Figs. 68 and 69), Epicycloid. FIG. 68. Hypocycloid. FIG. 69. divide the semi-circumference of the rolling circle into n equal parts, by points 1, 2, 3 . . . , and lay off these arcs (Al, A2, A3) along the circumference of the base circle, as Al', A2', A3', .... Describe circles with centers at 1', 2', 3', . . . and radii equal to the chords Al, A2, A3, . . .; then the required curve will be tangent to all these circles. Or, with as center, draw arcs through 1, 2, 3, . . ., meeting the radius OA in 1, 2, 3, . . ..and the radii Ol', O2', 03', . . . in 1", 2", 3", . . .; then from 1", 2", 3", . . . lay off arcs equal to 11, 22, 33, . . . respectively; the points thus reached will be points of the curve. The area OAP = a(c a) (c 2a) ~2c (rad u sin w) , where the upper sign applies to the epicycloid, the lower to the hypocycloid, and rad u = the radian measure of the angle u shown in Figs. 68 and 69. Arc AP = (4 o/c)(c a)(l - cos J4 w); arc AD = (4a/c)(c a). [In Fig. 69, D =4".] Radius of curvature at any point P is R = -^ '- sin Yiu\ at A, R = 0; c 2a at ), R 4o(c o) c 2a Special Cases. If a = ^c, the hypocycloid becomes a straight line, diam- eter of the fixed circle (Fig. 70). In this case the hypo trochoid traced by any OTHER USEFUL CURVES 153 point rigidly connected with the rolling circle (not necessarily on the circum- ference) will be an ellipse. If a = He, the curve generated will be the four- cusped hypocycloid, or astroid, (Fig. 71), whose equation is x^ + y^ = c^. If a = c, the epicycloid is the cardioid, whose equation in polar co- ordinates (axes as in Fig. 72) is r = 2c(l + cos 0). Length of cardioid = 16c. FIG. 70. Astroid. FIG. 71. Cardioid. FIG. 72. The Epitrochoid (or Hypotrochoid) is a curve traced by any point rigidly attached to a circle of radius a, at distance b from the center, when this circle rolls without slipping on the outside (or inside) of a fixed circle of radius c. The equations are x = (c a) cos ( ^ u J + 6 cos ( 1 ~ \ u \, d) sin \^-u) & sin ( 1 J u .where u = the angle which the V = (c moving radius makes with the line of centers; take the upper sign for the epi- and the lower for the hypo-trochoid. The curve is called prolate or curtate according as 6 < a or 6 > a. When & = a, the special case of the epi- or hypo- cycloid arises, j The Involute of a Circle is the curve traced by the end of a taut string which is unwound from the circumference of a fixed circle, of radius c. If QP Involute of Circle. FIG. 73. Spiral of Archimedes. FIG. 74. is the free portion of the string at any instant (Fig. 73), QP will be tangent to the circle at Q, and the length of QP = length of arc QA ; hence the construe- 154 ANALYTICAL GEOMETRY tion of the curve. The equations of the curve in parametric form (axes as in figure) are x = c(cos u + rad u sin w), y = c (sin u rad u cos w), where rad u is the radian measure of the angle u which OQ makes with the x-axis. Length of arc AP = c(rad w) 2 ; radius of curvature at P is QP. The Spiral of Archimedes (Fig. 74) is traced by a point P which, starting from O, moves with uniform velocity along a ray OP, while the ray itself revolves with uniform angular velocity about O. Polar equation: r = k rad 0, or r = a (0/360). Here a = 2irk = the distance, measured along a radius, from each coil to the next. In order to construct the curve, draw radii Ol, O 2, O3, . . . making angles - (360), -(360), - (360), . . with Ox, and along these radii lay n n n 123 off distances equal to - a, - a, - a, . n n n the points thus reached will lie on the spiral. The figure shows one-half of the curve, corresponding to positive values of 6. Construction for tangent and normal: Let PT and PN be the tangent and normal at any point P, the line TON being perpendicular to OP. Then OT = r*/k, and ON = k, where k = a/(2ir). Hence the construction. The radius of curvature at P is R = (k 2 + r 2 )^/(2fc 2 + r 2 ). To con- struct the center of curvature, C, draw NQ perpendicular to PN and PQ perpendicular to OP; then OQ will meet PN in C. Length of arc OP = \$k [rad 9 Vl + (rad 0) 2 + sinh -1 (rad 6)]. After many windings, arc OP = , approximately. Hyperbolic Spiral. FIG. 75. Logarithmic Spiral. FIG. 76. The Hyperbolic Spiral is the curve whose polar equation is r = o/rad 0. To construct the curve, take a series of points along Ox (Fig. 75) ; through each of these points, with center at O, draw an arc extending into the upper half of the plane; and along each of these arcs lay off a length = a. The points thus reached will lie on the curve. A line parallel to the x-axis, at distance o, is an asymptote of the curve. The curve winds around and around the point O without ever reaching it (asymptotic point) . The figure shows one- half of the curve, corresponding to positive values of 6. HPT and PN are the tangent and normal at any point P, the line TON being perpendicular to OP, OTHER USEFUL CURVES 155 then OT = a, and ON = r 2 /a. Hence a construction for the tangent and normal. Radius of curvature at Pis R = r/sin 3 v, where v = angle between OP and the tangent at P. Construction: At N draw a perpendicular to PN, meeting PO in Q; at Q draw a perpendicular toPQ, meeting PN in C; then C is the center of curvature for the point P. The Logarithmic Spiral (Fig. 76) ,-is a curve which cuts the radii from O at a constant angle v, whose cotangent is m. Polar equation: r = ae m fl . Here a is the value of r when 9=0. For large negative values of 0, the curve winds around O as an asymptotic point. If PT and PN are the tangent and normal at P, the line TON being perpendicular to OP (not shown in fig.), then ON = rm, and PN = r\A + w 2 = r/sin v. Radius of curvature at P is PN. The evolute of the spiral is an equal spiral whose axis makes an angle ^TT (log e m) /m with the axis of th'e given spiral. Area swept out by the radius r from r = (where 6 = -co) to r = r, is A = rV(4ra) = half the triangle OPT. Length of arc from O to P = s = r/cos v = PT. The Tractrix, or Schiele's Anti-friction Curve (Fig. 77) , is a curve such that the portion PT of the tangent between the point of contact and the z-axis is constant = o. Its equation is x = + a I cosh" 1 M T Tractrix. FIG. 77. = a ( or, in i _ y parametric form, x = a [t tanh t], y = a/cosh t. (For tables of hyper- bolic functions, see p. 60.) The z-axis is an asymptote of the curve. Length of arc BP = a log e (a/y}. The evolute (locus of centers of curvature) is the catenary whose lowest point is at B, and whose directrix is Ox. The Cissoid (Fig. 78) is the locus of a point P such that OP, laid off on a variable ray from O, is equal to BD, the portion of the ray lying between a fixed circle through O and a fixed tangent at the point A opposite O. If a is the radius of the circle, the polar equation is r = 2a sin 2 6 /cos 6. Rec- tangular equation, y*(2a x) = x 3 . Cissoid. FIG. 78. The Lemniscate (Fig. 79) is the locus of a point P the product of whose distances from two fixed points F, F r is constant, equal to Yt o 2 . The distance FF f = a^/2. Polar equation is r = a A/cos 26. Angle between OP and the normal at P is 29. The two branches of the curve cross at right angles at O. 156 ANALYTICAL GEOMETRY Zr H Maximum y occurs when 9 = 30 and r = a/V^ and is equal to H a Area of one loop = a 2 /2. The Helix (Fig. 80) is the curve of a screw thread on a cylinder of radius r. The curve crosses the elements of the cylinder at a con- stant angle, v. The pitch, h, is the distance between two coils of the helix, measured along an element of the cylinder ; hence h = 2irr tan v. Length of one coil = \/(27rr) 2 + h 2 = 27rr/cos v. To construct the projection of a helix on a plane containing the axis of the cylinder, draw a rectangle, breadth 2r and height h, to represent the plane, with a semicircle below it, as in the figure, to represent the base of the cylinder. Divide h into equal parts (here 8), num- bered from 1 to 8; think of the circumierence as also divided into 8 equal parts, represented on the semicircle by numbers from 1' to 4' and back again from 4' to 8'. Then the point of intersection of a horizontal line through 1,2, . . . with a vertical line through 1', 2', ... will be a point of the required projection. If the cylinder is X, ^x^ X s 2 ^s' ^^ / \Jr & -*S* 2' Helix. FIG. 80. rolled out on a plane, the development of the helix will be a straight line, with slope equal to tan v. DIFFERENTIAL AND INTEGRAL CALCULUS DERIVATIVES AND DIFFERENTIALS Derivatives and Differentials. A function of a single variable x may be denoted byf(x),F(x), etc. The value of the function when x has the value XQ is then denoted by f(xo),F(xo), etc. The derivative of a function y = f(x) may be denoted by f'(x), or by dy/dx. The value of the derivative at a given point x = XQ is the rate of change of the function at that point; or, if the function is represented by a curve in the usual way (Fig. 1), the value of the derivative at any point shows the slope of the curve (that is, the slope of the tangent to the curve) at that point (positive if the tangent points upward, and negative if it points downward, moving to the right) . The increment, Ay (read: "delta y"), in y is the change produced in y by increasing x from XQ to XQ + Ax; that is, Ay = f(x + Ax) - /(z ). The differ- ential, dy, of y is the value which Ay would have if the curve coincided with its tangent. (The differen- tial, dx, of x is the same as Ax when x is the inde- pendent variable.) Note that the derivative depends only on the value of XQ, while Ay and dy depend not -^ IG * only on XQ but also on the value of Ax. The ratio Ay /Ax represents the slope of the secant, and dy/dx the slope of the tan- gent (see Fig. 1). If Ax is made to approach zero, the secant approaches the tangent as a limiting position, so that the derivative = f'(x) = j A ,v. -i- rv i A i A / -i. n i A- i "-~~> My The symbol "lim" in connection with Ax == means "the limit, as Ax approaches 0, of ..." [A constant c is said to be the limit of a variable u if, whenever any quantity m has been assigned, there is a stage in the variation- process beyond which |c u\ is always less than m; or, briefly, c is the limit of u if the difference between c and u can be made to become and remain as small as we please.] To find the derivative of a given function at a given point: (1) If the function is given only by a curve, measure graphically the slope of the tangent at the point in question; (2) if the function is given by a mathematical expression, use the following rules for differentiation. These rules give, directly, the differential, dy, in terms of dx\ to find the derivative, dy/dx, divide through by dx. Rules for Differentiation. (Here u,v,w,. . . represent any functions of a variable x, or may themselves be independent variables, a is a constant which does not change in value in the same discussion; e 2.71828.) 1. d(a + u) = du. 2. d(au) = adu. 3. d(u + v + w + . . .) = du + dv + dw + . . . . 4. d(uv) = udv + vdu. . (du , dv dw \ 5. d(uvw . . . ) = (uvw ...)( 1 1 h . ) \ u v w I 6 d u = vdu -udr, t V V 2 7. d(u m ) = mu m - l du when m is not 157 158 DIFFERENTIAL AND INTEGRAL CALCULUS = 2wdu; d(w 3 ) _du_ 2V 'u = *?. u 14. d sin M = cos udu. 16. d cos w = sin udu. 18. d tan u = sec 2 wdw. dw 20. d sin- 1 w Thus, d(w 2 ) ,- 8. dVu = 10. d(e M ) = 12. 3w 2 dw; etc. 9. 11. d(a w ) = (log* a)a"dw. 13. d lo glo w = (logwe) u : (0.4343. . )^. 22. d cos- 1 u = 15. d esc M = cot u esc u du. 17. d sec u = tan u sec w du. 19. d cot w = esc 2 w du. du 21. d csc- J w = - - 1 d sec- 1 u = dw 24. d tan- 1 w = 1 + w 2 26. d log sin u = cot w du. 25. d cot- 1 u = 27. d log tan du 1 + w* 2du sn 28. d log cos M = tan u du. 29. d log cot u = 30. d sinh w = cosh u du. 32. d cosh u = sinh w du. 34. d tanh w = sech 2 u du. 36. d sinh- 1 M = f sin 2w 31. d csch w = csch u coth wdu. 33. d sech u = sech w tanh w du. 35. d coth w = csch 2 w du. 37. d csch- 1 M = - + 1 38. d cosh- 1 M = 40. d tanh- 1 u du \/u* - I du 39. d sech- 1 M = - dw 41. d 1 - u* 1 - u* 42. d(u v ) = (u v ~ l )(u logeu dv +vdu~). Derivatives of Higher Orders. The derivative of the derivative ia called the second derivative; the derivative of this, the third derivative; and BO on. Notation: if y = f(x), /'(*) = D,y dx' ,; etc. NOTE. If the notation fry/dx* is used, this must not be treated as a fraction, like dy/dx' but as an inseperable symbol, made up of a symbol of operation, d 2 /dx 2 , and an operand y The geometric meaning of the second derivative is this: if the original function y = f(x) is repre- sented by a curve in the usual way, then at any point where f"(x) is positive, the curve is concave upward, and at any point where f"(x) is negative, the curve is concave downward (Fig. 2). When f"(x) - 0, the curve usually has a point of inflection. Fio. 2. Differentials of Higher Orders. The differ- ential of the differential is called the second differential; the differential of DERIVATIVES AND DIFFERENTIALS; MAXIMA AND MINIMA 159 this, the third differential; etc. These quantities are of little importance except in the case where dx = a constant. In this case dy=f(x-)dx; d*y =/"(*)(<**); d z y = /'"(*) -(dx) z ; . . . The first, second, third, etc., differentials are close approximations to the first, second, third, etc., differences (p. 115), and are therefore sometimes useful in constructing tables. Thus, denoting the first, second, third, etc., differences by >', D", D'", etc., and, assuming always that dx a constant, ' =dy+Kd*y +Kd*y + Kidiy + . . . ; d*y = D>" - % D"" + . .' . D" = d*y + d 3 y + Vi2 d*y + . . . ; d z y = D" - D"' + itfa D"" + . . . D'" = d*y + % d*y + . . . ; dy = D' - H D" + H D'" - H D"" + . . . Functions of Two or More Variables may be denoted by f(x, y, . . . ), F(x, y, . . .),etc. The derivative of such a function u = f(x, y, . . .) formed on the assumption that x is the only variable (y, . . . being regarded for the moment as constants) is called the partial derivative of u with respect to x, and is denoted by f x (x,y), or D x u, or -^-, or ^-- Similarly, the partial dx ox derivative of u with respect to y is f v (x,y), or D v u, or , or -r-- dy dy NOTE. In the third notation, d x u denotes the differential of u formed on the assump- tion that x is the only variable. If the fourth notation, du/'dx, is used, this must not be treated as a fraction like du/dx; the d/dx is a symbol of operation, operating on u, and the " dx " must not be separated. Partial derivatives of the second order are denoted byfxx, fx u , f vv , or by D\u, -^ -' , .. J ox z oxoy Similarly for higher derivatives. Note that/xj, = f vx . If increments A#, Ay, (or dx, dy) are assigned to the independent variables x, y, the increment, Aw, produced in u = f(x,y) is AM = f(x + Az, y + Ay) - f(x,y) ; while the differential, du, that is, the value which Aw would have if the partial derivatives of u with respect to x and y were constant, is given by du = (fj-dx +V v )'dy. Here the coefficients of dx and dy are the values of the partial derivatives of u at the point in question. If x and y are functions of a third variable t, then the equation expresses the rate of change of u with respect to t, in terms of the separate rates of change of x and y with respect to t. For the graphical representation of u = f(x,y), see p. 178. Implicit Functions. If f(x,y) = 0, either of the variables x and y is said to be an implicit function of the other. To find dy/dx, either (1) solve for y in terms of x, and then find dy/dx directly; or (2) differentiate the equa- tion through as it stands, remembering that both x and y are variables, and then divide by dx; or (3) use the formula dy/dx = (/*//,/), where f x and f y are the partial derivatives of f(x,y~) at the point in question. MAXIMA AND MINIMA A Function of One Variable, as y = f(x), is said to have a maximum at a point x = x<\, if at that point the slope of the curve is zero and the concavity Dx(D u u), Dlu, or by -^ -' , .. J -^ -' the last symbols being "inseparable." 160 DIFFERENTIAL AND INTEGRAL CALCULUS FIG. 3. downward (see Fig. 3) ; a sufficient condition for a maximum is f(xo) = and /"(ZQ) negative. Similarly, /(z) has a minimum if the slope is zero and the concavity upward; a sufficient condition for a minimum is /'(x ) = and /"(XQ) positive. If /'(#o) = and f' f (xo) = and f"(xo) 7* 0, the point XQ will be a point of inflection. If f(x ) = and f"(xo) = and f'"(xo) = 0, the point x will be a maximum if /""(XQ) < 0, and a mini- mum if f""(xo) > 0. It is usually sufficient, however, in any practical case, to find the values of x which make f(x) = 0, and then decide, from a general knowledge of the curve, which of these values (if any) give maxima or minima, without investigating the higher derivatives. A Function of Two Variables, as u = f(x-,y), will have a maximum at a point (x ,y ) if at that point /* = 0, f y = 0, and fxx < 0, f vv < ; and a minimum if at that point f x = 0, f u = 0, and f xx > 0, f yy > 0; provided, in each case, (/**) (f yv ) (f xy } 2 is positive. If /* =0 and f v = 0, and f x x and f yy have opposite signs, the point (#0,2/0) will be a "saddle point" of the surface representing the function (p. 178). EXPANSION IN SERIES The range of values of x for which each of the series is convergent is stated at the right of the series. Arithmetical and Geometrical Series, and the Binomial Theorem. See p. 114. Exponential and Logarithmic Series. a>0, where ra = log* a = (2.3026) (logio a). x x x X* Or* X* X* - 1 < x < + oo. X a X* X 6 X 8 C08I = 1--+---+--. . .. -.<,< + .. x 3 2x 6 17x 7 62x 9 ' 1 x x 3 2x 6 x 1 cot*---------. . .; tan- 1 y = y-- + --- + ...; - 1 y + 1. o O / cos" 1 y = H?r sin~' y; cot" 1 y = ^iir tan 1 y. Series for the Hyperbolic Functions (x a pure number). X 3 X 6 X 7 sinh x==x +^7 + 7 + 7J + ---; -eo. X 2 X 4 X 6 coshx = 1 + + + + . . .; -oo< x [a + s(x - a)]}/n! = {(1 - O w ~ l /<">[<* + t(x - a)]}/(n - 1)! where s and t are certain unknown numbers between and 1 ; the s-form is due to Lagrange, the /-form to Cauchy. The error due to neglecting the remainder term is less than (P n )x n , or 162 DIFFERENTIAL AND INTEGRAL CALCULUS (Qn)( x ~ ) n where P n , or Q n , is the largest value taken on by P n , or Q n , when s or t ranges from to 1. If this error, which depends on both n and x, approaches as n increases (for any given value of x) , then the general - expression-with-remainder becomes (for that value of x) a convergent in- finite series. The sum of the first few terms of Maclaurin's'series gives a good approxi- mation to f(x) for values of x near x = 0; Taylor's series gives a similar ap- proximation for values near x = a. Fourier's Series. Let f(x) be a function which is finite in the interval from x = c to x = + c and has only a finite number of discontinuities in that interval (see note below), and only a finite number of maxima and minima. Then, for any value of x between c and c, f(x~) 00+ cos + 02 cos --- \- as cos - -- \- c c c . TTX , . 2WX . 3-7TX + &i sin +62 sin - + &3 sin -- c c c where the constant coefficients are determined as follows: /(0COS dl, C /(<) sin dt. c In case the curve y = f(x) is symmetrical with respect to the origin, the a's are all zero, and the series is a sine series. In case the curve is sym- metrical with respect to the y-axis, the 6's are all zero, and a cosine series results. (In this case, the series will be valid not only for values of x between c and c, but also for x = c and x c.) A Fourier's series can be inte- grated term by term; but the result of differentiating term by term will in general not be a convergent series. NOTE. If x = xo is a point of discontinuity, f(xo) is to be defined as ^[fi(xo) + /2(xo)], where fi(xo) is the limit of f(x) when x approaches xo from below, and MXO) is the limit of f(x) when x approaches xo from above. ^N- FIG. 4. o FIG. 5. H*-' /* / / I / I * FIG. 6. Examples of Fourier's Series. 1. If y = f(x) is the curve in Fig. 4, _ h _ 4A / THC 1 STI V 2 ~ K* \ COS c 9 C S c 2. If i/ = /(x) is the curve in Fig. 5, 4h I . TTX 1 . Zirx 1 5irx , 25 C S ^- + 5irx 3. If y = /(x) is the curve in Fig. 6, 2h I . TTX 1 . 27TZ y = ~ 8m - INDETERMINATE FORMS; CURVATURE 163 % INDETERMINATE FORMS In the following paragraphs, f(x), g(x) denote functions which approach 0; F(x),G(x) functions which increase indefinitely; and U(x) a function which ap- proaches 1 ; when x approaches a definite quantity a. The problem in each case is to find the limit approached by certain combinations of these functions when x approaches a. The symbol = is to be read "approaches." CASE 1. "jj-" To find the limit of f(x)/g(x) when /(x) = and0(z) = 0, use the theorem that lim = lim where f'(x) and g'(x) are the derivatives of f(x) and g(x). This second limit may be easier to find than the first. If f'(x) = and g'(x) = 0, apply the same theorem a second time: Hm^~ " = lim ^7^; and so on. g'(x) Q"(X) CASE 2. "-^-" If F(x) = oo and(?(z) = oo, then li precisely as in Case 1. CASES. "O-oo." To find the limit of f(x) -F(x) when f(x) = and F(x) = oo, write lim [f(x)-F(x)] = lim , * s , or = lim ^ ' , . ; then proceed as in Case 1 or Case 2. CASE 4. "0." If /(*) = and g(x) = 0, find lim [/(x)f (x) as follows: let y = [f(x)}^, and take the logarithm of both sides thus: log y = (/(x) log e /(x) ; next, find lim [g(x) log e /(x)], = m, by Case 3; then lim y = e m . CASE 5. "1." If U(x) = 1 andF(x) = oo, find lim [C7(x)]^ (x) as follows: let y = [U(x)\ F ^ x \ and take the logarithm of both sides, as in Case 4. CASE 6. " coo." if p(x) = ooand f(x) = 0, find lim [F(x)] f(x) as follows: let y = [F(x)] f(x \ and take the logarithm of both sides, as in Case 4. CASE 7. " oo- oo." If F(x) = oo and G(x) = oo, write lim [F(z) O(x)] 1 1 = lim -- ; then proceed as in Case 1. Sometimes it is shorter to ex- F(x) -G(x) pand the functions in series. It should be carefully noticed that expressions like 0/0, o / 00 . etc., do not represent mathematical quantities. CURVATURE The radius of curvature R of a plane curve at any point P (Fig. 7) is the distance, measured along the normal, on the concave side of the curve, to the center of curvature, C, this point being the limiting position of the point of intersection of the nor- mals at P and a neighboring point Q, as Q is made to ap- proach P along the curve. If the equation of the curve ia V =/(*), ds _ [1 + (yO']?* ~ du ~ g" FIG. 7. 154 DIFFERENTIAL AND INTEGRAL CALCULUS where ds = -\/dx 2 + dy 2 = the differential of arc, u = tan" 1 [/'(a;)] = the a,ngle which the tangent at P makes with the a>axis, and y f = f (x) and y" = /" (x) are the first and second derivatives of f(x) at the point P. Note that dx ds cos u and dy = ds sin u. The curvature, K, at the point P, is K = 1/R = du/ds; that is, the curvature is the rate at which the angle u is changing with respect to the length of arc s. If the slope of the curve is small, **/<*). If the equation of the curve in polar co-ordinates is r = /(0) , where r = radius vector and 6 = polar angle, then r 2 - rr" + 2(r') 2 where r' = /'(*) and r" =/"(0). The evolute of a curve is the locus of its centers of curvature. If one curve is the evolute of another, the second is called the involute of the first. INDEFINITE INTEGRALS An integral of f(x)dx is any function whose differential iaf(x)dx, and is denoted by J"f(x)dx. All the integrals of f(x)dx are included in the ex- pression y*/(30ffcc+ C, where t ff(x)dx is any particular integral, and C is an arbitrary constant. The process of finding (when possible) an integral of a given function consists in recognizing by inspection a function which, when differentiated, will produce the given function; or in transforming the given function into a form in which such recognition is easy. The most common integrable forms are collected in the following brief table; for a more extended list, see B. O. Peirce's "Table of Integrals" (Ginn & Co.). GENERAL, FORMULAE 1. fadu = afdu = au + C 2. J* (u + v)dx = fudx -j- fvdx 3. fudv = uv -f-odu 4. fj(x)dx = f f[F(y}}F f (y)dy, x = F(y) 5- fdyff(x,y}dx = f dxf f(x,y}dy. FUNDAMENTAL INTEGRALS _ x n+i 6. Jx n dx = + C; when n ^ - 1 7. y = log x + C = log e ex 8. J*e x dx = e x + C 9. ^sin xdx = cos x + C 10. ^cos xdx = sin x + C tan x + C tan' 1 x + C = - cot- 1 x + c RATIONAL FUNCTIONS _L ki^n+1 16. 17. 19. 20. INDEFINITE INTEGRALS 1 dx 1-65 = loge (a + bx} is. (a 6(0 dx loge \-C = tanh" 1 * +C, + C = - coth- 1 x + C, 24 r dx = - J a + 2bx,+ ex 2 b + when x < 1 when z > 1 when o > 0, 6 > when ac - 6 2 > ; when & - ac > 0; dx A+ 26. 27. , if /(x) is a polynominal of higher than the first degree, divide by the denominator before integrating. dx 1 6 + ex (a + 2bx 2(ac b z )(p 1) (a (2p - 3)c 28 -^(^f^ nx)dx 2(oc - n - 1) ** (o + 2bx I 2c(p - 1) "(a +2bx + me rib s* dx ~c ^ (a + 2bx + 29. +bx) n dx (m dx 166 DIFFERENTIAL AND INTEGRAL CALCULUS IRRATIONAL FUNCTIONS + C - 1 + C = - cos- 1 + c a a 'a + bx, and use 21 and 22 . = log* [x + Va 2 + x 2 ] +C= sinh- 1 + c = log e [x + V* z - a 2 ] + C = cosh" 1 - + c 38. y 1 + 2bx + ex 2 Vc when c > 0; = ^- sinh" 1 b +^ x = + C , when ac -6 2 > 0; 7 tc -6 2 zcosh- 1 -^^ + C, when 6 2 - ac > 0; = -^Lsin' 1 b+CX + C, when c < 39. y 40. y - V 2 + # 2 + sinh x he a INDEFINITE INTEGRALS 167 - a 2 da; = V* 2 - a 2 - loge (x + V* 2 - a 2 ) + C 44. TRANSCENDENTAL FUNCTIONS 45. 46. y ax a 2 x 2 47. y loge xdx = x loge x x + C 4 8 . 49 . 71 p _ + c x 50. y*sin 2 xdx = \i sin 2x + \to + C = M sin x cos x + Ha; + C 51. y*cos 2 x dx = J4 sin 2x + H + C = % sin x cos x + Hx -+- C /> . cos mx , / sin mx 52. / sm mx dx = h C 53. / cos mx dx = 1- C m m / . cos (m + n)x cos (m ri)x 54. / sm mx cos nx dx = f- C 2(m + n) 2(m n) /^ . sin(m n)x sin(m + n)x , 55. / sm mx sin nx dx = 7 '- \- C J 2(m - n) 2(m + n) Kc p sin(m ri)x sin(m -f- ri)x , oo. / cos mx cos nx ax = -4- C 2(m n) 2(m + n) 57. J tan xdx = log cos x + C 58. y*cot xdx = log sin x + C 59. f- - = loge tan ~ + C 60. /* = log tan ( - + - ) + < sm x 2 *^ cos x \4 2/ 63. /'sin x cos a; da; = ^ sin 2 x + C 64. /"- *X t-' ai cos x dx sin x cos x - cot - + C = log, tan x + C 65.*y*sin n xdx = 66.*y*cos n xdx = sin x cos" n , * -1 n - \ f 2 x dx n If n is an odd number, substitute cos x =- z or sin a; = z. 168 67. DIFFERENTIAL AND INTEGRAL CALCULUS tan' ~ z xdx / cot n l x r> 68. J cot* xdx = _ J cot n ~ 2 xdx 69. r-*L_ = J sin* -r fw. ~ 2 (n n ~ r <* n I** gin"" 2 TO. y dx sin" x dx cos n x (n 1) cos""" 1 x n 1^ cos n ~ 2 x sin p+1 xcos 9 ~ 1 x k r . 71. J sm p x cos 9 xdx = 4 /*sin p xcos- J xdx P + 3 P + o 4 6 cos x & & J a 4 6 cos x when a 2 < 6 s ^ cos x dx _ x a r> dx 75 ' J n 0- h o -r = T ~ fc / /i 4- 7> nna -r "*" 76. r * ** a 4- ^A + 77. / ; 47 a+ = log. (a 4 b cos x) 4 C COS X B cos x 4 C sin x , . / : dx = A I 6 cos x 4 c sin x ** a 4 cos y dy dy pcosy a + p cos y where b = p cos w, c = p sin w and z M a sin bx b cos & 78. 79. 80. 81. 82. 83. sin y dy a 4 pcosy' war 1 xdx = xsin- 1 ^ + l - & + C cosT 1 xdx = xcos~ l x \/l x 2 + C tan" 1 xdx = x tan" 1 x - J4 log e (1 + x 2 ) 4- C cot'^dx = x cot" 1 x + ^log (1 4 z a ) 4 C If p or g is an odd number, substitute eos z = z or einx . DEFINITE INTEGRALS 169 84. y* sinh xdx = cosh x + C 85. y tanh xdx = log, cosh a: + C 86. y cosh x dx = sinh a; + C 87. fcoth xdx = log a sinh x + C 88. y sech xdx = 2 tan" 1 (e*) + C 89. fcach xdx = loga tanh (x/2) +C 90. A* sinh 2 xdx = ^ sinh a: cosh x MX + C 91. f cosh 2 xdx = \ The equation for damped vibration: ~- + 26 + a 2 y = 0. arc 2 dx Case I. If o 2 - 6 2 > 0, let m = Va 2 - 6 2 . Solution: y = Ci e~ bx sin (mx + ^2) or y = e~* x [Cz sin (mx) + C 4 cos (mx)] Case II. If a 2 - 6 2 = 0, solution is y = e~ bx [Ci + Ctx]. Case III. If a 2 - 6 2 < 0, let n = V& - a 2 . Solution: y = Cie"** sinh (nx + C 2 ) or y = C 3 e~ (b+n)x + C 4 e~ (6 ~ n)a; d*y dy c (13) 3 + 26- h o 2 y = c. Solution: y = : 1- yi, where y\ = the solu- ax 2 ax a 2 tion of the corresponding equation with second member zero [see (12) above]. (14) -^ + 26-^ + a*y = c sin(fec). Solution: ax* ax y = R sin(kx - S) + yi, where R = c/V(a 2 - k 2 ) 2 + 46 2 A; 2 , 26fc tan Solution: y = y + y\, where y =-- any particular solution of the given equation, and y\ = the general solution of the corresponding equation with second member zero [see (12) above]. If 6 2 > a 2 , y = - b* - a 2 where m,\ = b + \/6 2 q 2 and m z = 6 If 6 2 x j(x) dx \ . GRAPHICAL REPRESENTATION OF FUNCTIONS For graphical methods in statistics, etc., see W. C. Brinton's "Graphical Methods for Presenting Facts" EQUATIONS INVOLVING TWO VARIABLES The Curve y = f(x). To represent graphically any function, y, of a single variable, x, lay off the values of x as abscissae along a uni- formly graduated horizontal axis, whose positive direc- tion (as usually chosen) runs to the right, and at each point on this z-axis erect a perpendicular (called an ordi- nate) whose length represents the value of y at that point. The unit of measurement for the y-sca\e, whose positive. direction (as usually chosen) runs upward, need jp IG j not be the same as the unit for the a>scale. Draw a smooth curve through the extremities of the ordinates; this is the graph of the given function in rectangular co-ordinates, or the curve of the function. To measure graphically the rate of change of the function at any point P (Fig. 1), draw the tangent atP; then rate of change at P = RT /PR, where RT and PR are measured in units of the y-axis and x-axis, respectively. This ratio, which is positive if RT runs upward, negative if RT runs down- ward, is equal to the derivative of the function at the point P (see p. 157). Graphs of Important Functions. Figs. 2-9 show the graphs (in rec- tangular co-ordinates) of the most important elementary functions, namely: The linear function, y = mx + b (Fig. 2). The power functions, y = x n [n positive (parabolic type) ; n negative (hyperbolic type)] (Fig. 3). The exponential function, y = 10* or y =e x , and the logarithmic function, y = Iog 10 x or y = log e x (Fig. 4). The trigonometric functions (Fig. 5), and the inverse trigonometric functions (Fig. 6). The hyperbolic functions (Figs. 7 and 8) and the inverse hyperbolic functions (Fig. 9). Various special functions (Figs. 10-12). By a slight modification, each of these diagrams may be made to represent a somewhat more general function than that for which it is primarily intended. For, if x is replaced by a; a in the equation, this merely requires re-number- ing the x-axis so that each number is moved a units to the left; and similarly, if y is replaced by y b in the equation, this merely requires re-numbering the y-axis so that each number is moved b units downward. (Such a change is called a translation of the curve to the right, or upward.) Further, if x is replaced by x/c [or y by y/c] in the equation, it is merely necessary to multiply each of the numbers written along the x-axis [or y-axis] by c, in order to adapt the graph to the new equation. (Such a change is called a "stretch- ing" of the curve along one of the axes.) Empirical Curves. Any set of values of two variables x and y can be represented by plotting the points (x,y) on rectangular co-ordinate paper, and drawing a smooth curve through these points. The points which correspond to actual data should be clearly indicated by small circles or crosses, inter- mediate points being spoken of as interpolated points. While this process of graphically interpolating a continuous series of points between given values is usually fairly safe, the process of extrapolation that is, extending the curve beyond the range of the given values, is dangerous. 173 174 GRAPHICAL REPRESENTATION OF FUNCTIONS Linear function, y = ma; + b. FIG. 2. / o i (Parabolic Type) (Hyperbo/fc Type) Power function, y = x n . FIG. 3. ff Exponential function (10* or e x ~). Logarithmic function (logic x or log e x) . FIG. 4. Inverse trigonometric functions. FIG. 6. -4FJX Trigonometric functions. FIG. 5. To Find a Mathematical Equation to Fit a Given Empirical Curve. This problem is one which in general requires much patience and ingenuity. Only the simplest cases can be mentioned here. CASE 1. If the given empirical curve is a straight line, then the law con- necting the given values of x and y is y = mx + 6, where ra = the slope of the line, and 6 = the value of y at the point where the line crosses the 2/-axis. If EQUATIONS INVOLVING TWO VARIABLES 175 i z 3 Hyperbolic functions and inverse hyperbolic functions. FIG. 7. FIG. 8. FIG. 9. y.,< K-or... v jr.02-... s /raaJ FIG. 10. /f.-/.5- /I /-f **** FIG. 12. the points lie only approximately on a straight line, the best position for this line can usually be found by stretching a black thread among the points; or, assume a law of the form y = mx -\- b, and, by substituting in this formula n pairs of values of x and y, obtain n equations connecting the coefficients ra and b; various pairs of these equations may then be solved for m and 6, and the average of the results taken. Or, if great accuracy is required, all nof the equations may be solved for m and 6 by the method of least squares (p. 121). If any law of the formj(x,y') = m-F(x,y) + 6 is suspected, where f(x,y) and F(x,y) are any expressions involving either x or y or both x and y, such a law may be tested by plotting F(x,y) instead of x, andf(x,y) instead of y, on rec- tangular cross-section paper, and seeing whether or not the points lie on a straight line. If they do, the form of the law is verified, and the values of m and b can be read from the figure as before. For example, if j/ 2 = mxy + &, a straight line will be obtained by plotting y 2 against xy. Again, if xy = bx + my, a straight line will be obtained by plotting y against y/x, since the equa- tion may be written y = b -f m (y/x)- CASE 2. If a law of the form y = cx n is suspected, plot the points (x,y) on logarithmic paper (see below). CASE 3. If a law of the form y =c-10 wa; [or y = c-e mx ] is suspected, plot the points (x,y) on semi-logarithmic paper (see below). 176 GRAPHICAL REPRESENTATION OF FUNCTIONS CASE 4. If the given curve resembles the logarithmic curve, y = log x, interchange x and y and proceed as in Case 3. CASE 5. If the given curve is a wavy line, resembling a sine or cosine curve, try an equation of the form y = a sin bx or y = a cos bx. If the heights of the waves diminish as x increases, try an equation of the form y = ae~ nx sin bx. [NOTE. Any periodic function (satisfying certain simple conditions) can be expressed by a Fourier's series (p. 162)]. CASE 6. A great variety of functions can be represented approximately by a polynomial of the form y = a + bx + ex 2 -f dx 3 + ex* + . . . , the first three or four terms being usually sufficient. To determine the coefficients a, b, c, . . . , most accurately, substitute in the formula all the given pairs of values of x and y, and solve the resulting equations for a,b,c, ... by the method of least squares (p. 121). CASE 7. Many simple curves can be represented approximately by an equation of the hyperbolic form, xy = c -f bx -f- ay, where a, b, and c are determined by substituting the co-ordinates of three conspicuous points of the curve. The lines x = a and y = b are the asymptotes of the hyperbola. The equation may also be written (x a) (y b) = k, where k = ab + c. Logarithmic Cross-section Paper. In this form of cross-section paper (Fig. 13), the distance from the origin to any point on the x- or y-axis is equal to the logarithm of the number written against that point. Thus, in Fig. 13 the distances (shown for clearness on two auxiliary scales X and Y) are the logarithms of the numbers written along x and y. Y v 50 100 x "~~t X FIG. 13. 3 4 56789 10 FIG. 14. Accurately made logarithmic paper can be obtained from the principal dealers in draftmen's supplies. Logarithmic paper can be easily con- structed, in case of need, by copying the logarithmic scale from any ordinary slide rule. The actual figures along the x- and y-axes are usually left for the user to insert; in so doing, notice that the numbers . . .,0.01, 0.1, 1, 10, 100, . . . , or such of them as may be needed to cover any given range of values, must be placed at the points of division which separate the main squares. It is often convenient, however, to omit the decimal point, num- LOGARITHMIC CROSS-SECTION PAPER 177 bering each square independently from 1 to 10. The length of the side of one square is called the unit or base of the logarithmic paper; the larger the unit, the finer the possible subdivisions of the scale. To plot a point (x,y) on logarithmic paper, for example, the point (3,5), means to find the point of intersection of the vertical line marked x 3 and the horizontal line marked y = 5. In interpolating between two lines, account should be taken of the fact that the divisions are not of uniform length. Any equation of the form y = cx n when plotted on logarithmic paper will be represented by a straight line whose slope is n. For, if y\ = cx\ n and yt = cx2 n , then yi/yz = (xi/xz) 11 , or (log y\ log yz) /(log x\ log xz) = n. The slope must be measured by aid of an auxiliary uniform scale. EXAMPLE. Let y = a; 3 ' 2 . When x = 1, y = 1; plot this point A on the logarithmic paper, and draw the straight line AE with a slope equal to % (Fig. 13). By the aid of this line, the value of y for any value of x between 1 and 100 can be read off directly; for example, if x = 2.50, y = 3.95, as shown by dotted lines, so that (2.50)/z = 3.95. To find the value of y for any value of x outside this range, note that moving the decimal point 2 places in x is equivalent to moving it 3 places in y. The line shown in Fig. 13 is thus equivalent to a complete table of three-halves powers. It will be noticed that this line crosses four squares of the logarithmic paper. By superposing these four squares the whole diagram may be condensed into a single square (Fig. 14), in which, however, the scales for x and y now give only the sequence of digits in the answer, the position of the decimal point having to be determined by inspection. To determine whether a given set of values, z and y, satisfies a law of the form y = cx n , plot the values on logarithmic paper, and see whether they lie on a straight line; if they do, then the given values satisfy a law of this form ; moreover, the slope of the line gives the value of n, and the value of y when x = 1 gives the value of c. If the plotted points fail to lie exactly in line, but form a curve slightly concave up- ward, try subtracting some constant b from all the y's, that is, move each point downward a distance equal to b units of the y-scale at that point. If it proves possible to choose b so that the resulting points lie in line, then the original values obey a law of the form y b = cx n , where n is again the slope of the line, and c is the value of y b when x = 1. (Conversely, if the curve is concave downward, try adding b to all the y's; that is, move each point upward; if the new points lie in line, the original values obey a law of the form y + b = cx n .) Another method of "straightening" the curve consists of adding some constant, a, to all the values of x, which has the effect of shifting all the points to the right or left (by varying amounts) ; if this method succeeds, the original values obey a law of the form y = c(x + a) n . Semi-logarithmic Cross-section Paper*. This form of paper (Fig. 15) has a logarithmic scale along y and a uniform scale along x. The ''scale value," k, of the paper is the number which stands, on the z-axis, at a dis- tance from the origin equal to the width of one of the main horizontal strips. Thus, in Fig. 15, each number shown along the auxiliary scale Y is the loga- rithm of the corresponding number along y, and each number shown along the auxiliary scale X is 1/fcth of the corresponding number along x (here k = 5). The number k, which may be chosen at pleasure, should be taken equal to some simple integer, as 1, 2, or 5, or some integral power of 10. In preparing the paper for use it is important to notice that the numbers . . .,0.01,0.1, 1, 10,100, . . . {or such of them as may be needed in any given case) must be placed along the 2/-axis at the points which mark the main lines of division between the horizontal strips; while the numbers . . ., 2fc, k, 0, + k, + 2k, . . . (or such of them as may be needed) must be placed along the rr-axis at uniform intervals, each interval (from to ft, from A; to 2k, etc.) being equal to the width of one of the main horizontal strips. The width of one of these strips is called the unit or base of the semi- *Made by the Educational Exhibition Co.. 26 Custom House St., Providence, R.I. 12 178 GRAPHICAL REPRESENTATION OF FUNCTIONS 10 x "zx logarithmic paper; the larger the unit, the finer the possible subdivisions of the scale. To plot a point (x,y}, as a: = 3, y 5, on semi-logarithmic paper means to find the point of intersection of the vertical line marked x = 3 with the horizontal line marked y = 5. Any equation of the form y = c-10 mz [or y c-e mx ] when plotted on semi-logarithmic paper with scale value k, will be represented by a straight line whose slope is km [or 0.4343 few.]. By a suitable choice of the scale value k, any given range of values of x can be brought within the size of the paper. Note that e = 10- 4343 . EXAMPLE. Given y = 4-10- - 1 * [or y = 4-e- - 1 *]. In Fig. 15, when x = 0, y = 4. _! " ' " ' By plotting this point (A) on the semi- logarithmic paper, with scale value 5, and FIG. 15. drawing through it a straight line with slope equal to 0.5 [or 0.217] a graphical representation is obtained from which, for any value of x, the corresponding value of y can be read off. If it is desired to condense the figure, several horizontal strips may be superposed on a single strip; this of course renders the decimal point in the y-scale undetermined (unless a separate y-scale is provided for each section of the graph). In order to determine whether a given set of values of x and y satisfy a law of the form y = c-W mx [or y = c-e mz ], plot the values of x and y on semi-logarithmic paper, with a suitable scale value k, and see whether they lie on a straight line; if they do so, the law is satisfied, and the values of m and c may be found as follows: m = the slope of the line divided by k [or the slope of the line divided by 0.4343/c], and c = the value of y when x = 0. If the plotted points fail to lie exactly in line, but form a curve slightly concave up- ward, try subtracting some constant b from all the y's, and plot the values thus modified; if & can be so chosen that the revised points lie in line, then the original values obey a law of the form y b = c-10 mx [or y b = c-e mx ], where m and c are to be found as before. If the curve is con- cave downward, add b, instead of subtracting; and replace y bby y + b in the law. Curves in Polar Co-ordinates. Any function, r, of a single vari- able, f>, can be represented by a curve in polar co-ordinates (p. 137). Lay off the given values of 6 as angles, the initial line Ox running toward the right, and the counterclockwise direction about the origin flQ 16 being taken as positive. Along the terminal side of each angle 0, lay off the corresponding value of r, forward if r is positive, backward if r is negative; and pass a smooth curve through the points thus determined. The rate of change of r with respect to 6 at a given point P is represented graphically as follows (Fig. 16): On the tangent at P drop a perpendicular OM from the origin; then r(MP/OM) represents the rate of change, dr/de, provided is measured in radians. Specially ruled polar co-ordinate paper is supplied by dealers in drafting supplies. EQUATIONS INVOLVING THREE VARIABLES The Surface z = f(x, y). Any function, z, of two variables, x and y, may be represented by a surface, as follows: Plot the given pairs of values of x and y as points in a horizontal x, y plane, called the base plane; at each of these points erect an ordinate, parallel to a vertical axis z, and representing EQUATIONS INVOLVING THREE VARIABLES 179 by its length the value of z at that point. Then conceive a smooth surface passed through the extremities of these ordinates: this surface is said to repre- sent the function. In practice, the ordinates may be made by implanting stiff vertical rods in a horizontal board of soft wood which serves as the base plane; the surface may then be constructed by filling in the spaces with plaster of Paris. Or, more simply, pieces of cardboard may be cut out to represent parallel plane sections of the surface, and then stood on edge in slots cut in the board to receive them. The units employed along x, y, and z need not be equal to each other. Contour-line Charts. All the points of a surface z = f(x, y) which are at any given height above the base plane form a curve on the surface, called a contour line of the surface. If each of these contour lines be projected on the base plane, and each labeled with the value of z to which it corresponds, a complete representation of the function z = f(x, y) is obtained, all in one plane. A topographical map, with contour lines showing elevations above the sea, and a weather map, with contour lines showing barometric pressure, are familiar' examples. If there are several values of z corresponding to any given point (x, y}, there will be several contour lines whose projections pass through that point. Contour-line Charts for Simultaneous Equations [of the form z - f(x,y), w = F(x,y~)]. In Fig. 17, plot the function z = f(x t y) by contour lines on an x,y plane, and plot the function w = F(x,y) by contour lines on the same x,y plane. Then every point on the diagram (either directly or by interpola- tion) is the intersection of four curves an z-curve, a y-curve, a z-curve, and a w-curve. Here, by "curve" is meant any line, straight or curved. By the aid of such a diagram, when the values of any two of these four variables are given, the values of the other two can be found. The method of use consists simply in entering the diagram along the two given curves (or lines), tracing them to their point of intersection, and then coming out again along the two curves (or lines) whose values are required. The best manner of num- bering the curves is indicated in the figure. Alignment Charts for Three Variables, t, u, v. Any relation between three variables, t, u, v, which can be thrown into one of the forms listed in later paragraphs, can be represented graphically by a very convenient form of diagram called an alignment chart. In the simplest form of an alignment chart for three variables there are three scales (straight or curved), along which the values of the three variables, t, u, v, are marked in such a way that any three values of t, u, v which satisfy the given equation are represented by three points which lie in line. Hence, if the values of any two of the vari- ables are given, the corresponding value of the third can be found by simply drawing a straight line through the two given points and reading the value of the point where it crosses the third scale. The most important methods of constructing alignment charts for three variables are described below. Where several methods are applicable in a given case, the best one must be determined largely by trial. For further informa- tion see M. d'Ocagne, "Traite de Nomographie" (Gauthier-Villars, Paris); Carl Runge, "Graphical Methods" (Columbia University Press) ; J. B. Peddle, "Construction of Graphical Charts" (McGraw-Hill); see also page 185. 180 GRAPHICAL REPRESENTATION OF FUNCTIONS Notation. In each of the equations which follow, U stands for any function of u alone, V for any function of v alone, and.Fi(0, Fz(t) for any func- tions of t alone. Any of these functions may reduce to a constant. The axes of x, y, and y' which are mentioned are of merely temporary use in con- structing the diagram, and the letters x, y, y' should not be written on the chart. It is not necessary that the axes be at right angles, provided the x of a point is always measured parallel to the z-axis, and its y parallel to the y-axis. Method 1. Given, an equation which can be thrown into the form U-Fi() + V-Fi(t) = 1, where, for the given range of values of u and v, the largest variations in U and V are less than a certain *number m. Draw a pair of (temporary) x,y axes (Fig. 18), and through the point x = 1 draw a third axis, which may be called the axis of y', parallel to the axis of y. In ordinary cases, the unit of measurement along x should be nearly equal to the full width of the paper. Now choose a unit for y and y' such that m times this unit will about equal the height of the paper, and plot, in the usual way, the points (x,y) given by FIG. 18. labeling each point with the value of t to which it corresponds. Connect these points by a smooth curve, which gives the -scale of the diagram. [If Fi(t)/Fz(t) = a constant, the -scale will prove to be a straight line parallel to the j/-axis.] Then, using the same units as above, plot along y the points given by y = U, labeling each point with the corresponding value of u\ and plot along y f the points given by y' = V, labeling each of these points with the corre- sponding value of v. This gives the u- and v-scales of the diagram. The three scales being thus constructed, the a;-axis may now be erased, and the diagram is ready for use. Any three points t , u, v which lie in line correspond to three values of t, u, v, which satisfy the given equation. The numbering on each scale should be shown at sufficiently frequent intervals to permit of easy interpolation. 200 100 ' 5 EO 4 10 5 2 U'V ' " f FIG. 19. u 200 - -100- O 50 J EXAMPLE 1 (Fig. 19). Let u 1>tt = t. By taking the logarithm of both sides, and dividing through by log t, reduce the equation to the form (log u) (I/log + (log t>) X (1.41/log - 1. Here U = log u, V = log v, Fi(t) <*> I/log t t F*(t) - 1.41/log t, and Z - 1.41/2.41 - 0.585, y - (l/2.41)log t. ALIGNMENT CHARTS 181 EXAMPLE 2 (Fig. 20). Let v = ut + 16 2 , which reduces to the form (- u/16)(l/0 + (/16)(l// 2 ) = 1. Here U -- u/16, V = t>/16, Fi(t) = 1/t, F 2 ) = 1/ J and x - 1/(1 + 0, 2/ = V(1 + 0- NOTE. If m = oo , values of and v which give large values of U and 7 cannot be shown within the limits of the paper. In such cases, the chart may be supplemented by a second chart, made according to Method 2, below. Method 2. Given, an equation which can be thrown into the form , _ -, U V where, for the given range of values of u and v, the largest variation in U is less than a certain number m. and the largest variation in V is less than a certain number n. Draw.a pair of temporary x,y axes, and having chosen a unit for the z-axis equal to about (l/m)th of the width of the paper, and a unit for the f/-axis equal to about (l/n)th of the height, plot the points (x,y) given by x = Fi(t), y =F 2 (0, labeling each point of this curve with the value of t to which it corresponds. Connect these points by a smooth curve, which gives the <-scale of the diagram. [If FiCO/ACO = a constant, the <-scale will be a straight line through the origin.] Then, using the same units as above, plot along x the values of 7, labeling each point with the corresponding value of u', and plot along y the values of F, labeling each point with the corresponding value of v. This gives the u- and v-scales of the diagram. On the chart as thus completed, any three points t, u, v which lie in line correspond to three values of t, u, v which satisfy the given equation. EXAMPLE (Fig. 21). Let t => (uv)/(u + ), which may be written in the form t/u + t/v = 1. Here U = u, V = v, Fi(t) = t, F 2 (t) - t. NOTE. If TO = oo and n = oo , values of u and v which give large values of U and V cannot be shown within the limits of the paper. In such cases the chart may be supplemented by a second chart, made according to Method 1, above. Method 3. Given, an equation which can conveniently be thrown into the form F 2 (0 = V'Fi(t) + U, where, for the given range of values of t, the largest variation in Fi(C) is less than a certain number m, and the largest variation inFz(f) is less than a certain number n. Draw a pair of temporary x,y axes, and, having chosen a unit for x equal to about (l/m)th of the width of the paper and a unit for y equal to about (l/n)th of. the height, plot the points (x,y) given by * = Fi(), y =F(0, labeling each point of the curve with the value of I to which it corresponds. Connect these points by a smooth curve, which forms the <-scale. Next, using the same unit for y as above, plot along the y-axis the values of U, labeling each point with the corresponding value of u. This gives the w-scale. Finally, with the origin as center, and any convenient radius, draw a circle cutting the z-axis in A. Along this circular arc, starting from A in the coun- terclockwise direction, lay off the angles whose slopes are equal to F, labeling each point of the arc with the value of v to which it corresponds. 182 GRAPHICAL REPRESENTATION OF FUNCTIONS This gives the v-scale, which in this case, however, plays a peculiar role, since, in using this form of chart, two straight lines are required instead of one. Thus: In order to determine whether three values, t, u, v, satisfy the given equation, lay one straight line through the points t and u, and another straight line through the point v and the origin; if these lines are parallel, the three values of t, u, v satisfy the equation. It will be noticed that the function of the r-scale here is to measure, in a certain sense, the slope of the line joining t and u. A chart of this type may be .called " an alignment chart with a sliding scale for one of the variables." , EXAMPLE (Fig. 22). Let sin u = sin 60 sin t cos 60cos t cos v, which may be put in the form (sin 60 sin t) = cos v (cos 60 cos t) + sin u. Here Fi(0 = cos 60 cos t, Fz (0 = sin 60 sin t, U = sin u, V = cos v. Method 4. Given, an equation which can be reduced to the form C7-F(0 + V = 0, sin u- fin 60iin t- cos 60cost cos v FIG. 22. where, for the given range of values of u and v, the largest varia- tions in U and V are less than a certain number m. In Fig. 23, draw temporary axes x, y, and y' , and choose the units as in Method 1. To construct the f-scale, which will now coincide with the a;-axis, plot along x the points for which 1 ~ 1 + F(t) ' labeling each point with the value of t to which it cor- responds. The it-scale, along the axis of y, and v- scale, along the axis of y' , are constructed exactly as in Method 1, and the finished chart is used in the same way. FIG. 23. 15000 V 150000 10000 FIG. 24. EXAMPLE (Fig. 24). Let v 0.196 thi, where u is to range from to 15,000 and v from to 150,000. The equation may be written in the form (- 10 u) (0.0196**) + v = 0. Here U = - 10 u, V = v, F(t) = 0.0196<. NOTE. If m = co , values of u and v which give large values of U and V cannot be shown within the limits of the paper. EQUATIONS INVOLVING FOUR VARIABLES [For simultaneous equations of the form z = f(x,y), w = F(x,y), see p. 179.] Alignment Charts for Four Variables. The extension of the methods of the alignment chart to the case x of four variables, say r, s, u, v, consists essentially in replacing the f-scale of the earlier diagram by a network of two scales, one for r and one for s. The point where a curve r = r\ and a curve s = si intersect may be spoken of as the point (ri,si). In the following equa- tions, U denotes as before any function of u alone, V any function of v alone; while Fi(r,s) and Fz(r,s) represent any functions of r and s. Method la. Given, an equation of the form E7-Fi(r,) + V-F 2 (r,s) = 1. EQUATIONS INVOLVING FOUR VARIABLES 183 Draw axes x, y, and y' as in Method 1, and plot the network of curves given by the equations [To do this (Fig. 25), find the point (x,y) that corresponds to each given pair of values of r and s, by direct substitution in the equations for x and y. Con- nect all the points for which r = 1 by a curve, and label it r = 1; connect all the points for which r = 2 by another curve, and label it r = 2 ; etc. This gives the family of r-curves. Similarly, through all the points for which a = 1 draw a curve labeled s = 1; through all the points for which s = 2 draw a curve labeled s = 2; etc. This gives the family of s-curves, intersect- ing the family of r-curves. Note, however, that if it is possible to eliminate s (or r-) from the equations that give x and y, the resulting equation in x, y, and r (or x, y, and s) can often be plotted directly for each given value of r (or of s).] Next, construct the u- and v-scales along the axes of y and y' as in Method 1. [The letters x, y, and y', and the units used in plotting along these axes, should be omitted from the finished diagram, as should also the axis of x.] In the chart, as thus completed, any three points, (r,s), u, and v which lie in a straight line, correspond to values of r, s, u, v which satisfy the given equation. Hence, when any three of these four values are given, the fourth can be found from the chart. FIG. 25. O"! 2 3 i 5 FIG. 26. Method 2a. Given, an equation of the form + = 1. U V Draw axes of x and y as in Method 2, and plot the network of curves given by x =Fi(r,s), y =F a (r,s). To do this, follow the plan outlined for a similar case under Method la. labeling each curve pf the r-family (Fig. 26) with the corresponding value of r. and each curve of the s-family with the corresponding value of s. Next, construct the u- and v-scales along the x- and y-axes, precisely as in Method 2. Then any three points, (r,s), u, and v, which lie in a straight line correspond to values of r, s, u, v which satisfy the given equation. Method 3a. Given, an equation of the form F 2 (r,s) = F-Fx(r,s) + U. Draw axes of x and y, as in Method 3, and plot the network of curves given by x = Fi(r,s), y = F 2 (r,s), following the plan outlined for a similar case under Method la, and labeling each curve of the r-family (or s-family) with the valvte of r (or s) to which it corresponds. Next, construct the w-scale 184 GRAPHICAL REPRESENTATION OF FUNCTIONS along the y-axis, and the v-scale along a circular arc, precisely as in Method 3. Then any three points, (r,s) u, and v, which are so related that the line through (r,s) and u is parallel to the line joining v with the origin, will corre- spond to values of r, s, u, v which satisfy the given equation. EXAMPLE for Method 3a (Fig. 27). Let cot v = cot r cos s + esc r sin s cot u, which may be written (cos r cot s) = cot v (sin r esc s) cot u. Here U = cot u, V = cot v, x z y 2 x 2 w 2 Fi(r,s) = sin r esc s, Fz(r,s) = cos r cots, whence + =1. . , = 1, csc 2 s cot 2 s sm 2 r cos 2 r BO that the s-curves are ellipses and the r-curves hyperbolas. Parallel Charts, or Proportional Charts, for Four Variables. In the following methods of representation there are four scales, one for each of the four variables, and the method of using the diagram consists in connecting two pairs of points by parallel lines. Method A. Given, an equation of the form R - S = U - V where R, S, U, V are any functions of the variables r, s, u, v, respectively. [It will be noted that any proportion R/S = U/V can at once be thrown into this form by taking the logarithm of both sides.] In Fig. 28, draw four vertical axes, yi, yz, y'l, y'z, such that the distance between y\ and 2/1 (which may be zero) is equal to the distance beween yz and 3/2, and so that the four zero points lie in line. Along these axes, using the same unit for all, plot the points given by yi =R, y'l = S, yz = U, 2/2 = V, and label each point with the value of r, s, u, or v to which it cor- responds. (The letters y\, yz, y'l, y'z are tem- porary, and should not appear on the diagram.) Then if the line joining two points r and u is parallel to the line joining two points s and v, the four values of r, s, u, v will satisfy the given equation. In this and the following methods, a parallel ruler, or a pair of draf tman's triangles, will be useful in reading the chart. A "key" stating which points are to be joined with which, should be clearly given on the diagram. EXAMPLE (Fig. 28). Let 32.2 vr = us 2 , or log r - 2 log s = log u - log (32.2 ). Here R = log r, S = 2 log s, U = log u, V = log (32.2 r). Method B. Given, an equation of the form R, _ J7 S ~ V In Fig. 29, draw a pair of axes, x,y, and parallel to them (or coinciding with them) a second pair of axes, xi,yi. Using any convenient horizontal unit, plot along x and xi the points given by x = R, x\ = U, and using any convenient vertical unit, plot along y and y\ the points given by y = S, y\ = V. Label each point with the value of r, s, u, v, to which it corresponds. (The letters x, y, x\, y\ should not appear on the diagram.) Then if the line joining two points r and s is parallel to the line joining two points u and v, the four values r, s, u, v will satisfy the given eouation. COt y - cot r cos s + esc r sin s cot a V r , Connect^?* %%} by Parallel Una. FIG. 27. EQUATIONS INVOLVING FOUR VARIABLES 185 Method C. Given, an equation of the form V U R - S In Fig. 30, take a pair of axes, x,y, and through the point x = 1 draw a third axis, y', parallel to y. Also, take a second pair of axes, 2,2/2, parallel to (or coinciding with) the axes of x and y. Having chosen a suitable unit for x and 2, and a suitable unit for y, y', and 3/2, lay off the values of R and 500- 100 M /'K? r s K'Y 40 5 3- : x \. 5 ~' 5 4 3 \ N V I 1 V 54 5 6 1 ' ' . i . . ^V* i r* i . 1 I 3 4 5 6 U (X,) FIG. 29.