Elements of Plane and Spherical Trigonometry |
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Page 15
... NOTE . It is sufficient to show that the two members are the same . - y 1st Proof . Substitute for tan u , x y x r X 2 ° for cos u , for cscu , y 1 , or 1 = 1 . X X = х r y 2d Proof . By [ 9 ] , tan u cos u = sin u , and by [ 1 ] , sin ...
... NOTE . It is sufficient to show that the two members are the same . - y 1st Proof . Substitute for tan u , x y x r X 2 ° for cos u , for cscu , y 1 , or 1 = 1 . X X = х r y 2d Proof . By [ 9 ] , tan u cos u = sin u , and by [ 1 ] , sin ...
Page 18
... NOTE . Throughout this work , the required angles will often be expressed in the nearest minute , as that is sufficiently accurate for all ordinary practical pur- poses , and spares the student the labor and waste of time in finding ...
... NOTE . Throughout this work , the required angles will often be expressed in the nearest minute , as that is sufficiently accurate for all ordinary practical pur- poses , and spares the student the labor and waste of time in finding ...
Page 22
... NOTE . - .. x = √ ( r + y ) ( r− y ) We may find x by ( b ) and check by ( a ) . COMPUTATION . ( 1 ) BY NATURAL FUNCTIONS u = 90 ° - 21 ° 47 ' 68 ° 13 ' . = y = 20 × sin 68 ° 13 ' = 20 × 92859 = 18.572 . x = 20 x cos 68 ° 13 ' = 20 x ...
... NOTE . - .. x = √ ( r + y ) ( r− y ) We may find x by ( b ) and check by ( a ) . COMPUTATION . ( 1 ) BY NATURAL FUNCTIONS u = 90 ° - 21 ° 47 ' 68 ° 13 ' . = y = 20 × sin 68 ° 13 ' = 20 × 92859 = 18.572 . x = 20 x cos 68 ° 13 ' = 20 x ...
Page 26
... NOTE . - This result can be obtained from [ 36 ] by making A : х COS u- · r ( a ) = u and Examples . 1. Required the angle of elevation ( CAB , Fig . 15 ) of a railway track at a point where a section of the track ( AB ) 3967.6 ft . in ...
... NOTE . - This result can be obtained from [ 36 ] by making A : х COS u- · r ( a ) = u and Examples . 1. Required the angle of elevation ( CAB , Fig . 15 ) of a railway track at a point where a section of the track ( AB ) 3967.6 ft . in ...
Page 27
... NOTE . — In computing the value of K by logarithms it will be most con- venient to find 2 K first , and then take half of it . 3. Given u = 19 ° 36 ' , y = 11.089 ; find K = 172.7 . 4. Given u = 40 ° 30 ' , x = = 12.42 ; find K. 5 ...
... NOTE . — In computing the value of K by logarithms it will be most con- venient to find 2 K first , and then take half of it . 3. Given u = 19 ° 36 ' , y = 11.089 ; find K = 172.7 . 4. Given u = 40 ° 30 ' , x = = 12.42 ; find K. 5 ...
Common terms and phrases
9 cos 9 9 cot 9 sin 9 A₁ A₁OP acute angle adjacent angle are given base circle colog cologarithm cos² cot 10 tan COTANGENTS csc² Cyclically decimal denoted distance divided equal Exercise express Find the angle Find the area find the number Find the values formulas Hence hour-angle hype hypotenuse included angle isosceles triangle latitude law of cosines law of sines log cot mantissa natural functions negative number corresponding number whose logarithm OA₁ opposite angles perp perpendicular plane polar triangle positive radian radius relation right angle right triangle sec² signs sin 9 cos sin b sin sin² solution solved spherical triangle STATEMENT subtract tan² tanc tangent three angles three sides Trigonometry Whence ΙΟ
Popular passages
Page 58 - THE MACMILLAN COMPANY, 66 FIFTH AVENUE, NEW YORK. This book should be returned to the Library on or before the last date stamped below. A fine of five cents a day is incurred by retaining it beyond the specified time. Please return promptly.
Page 9 - Hence, to find the characteristic of the logarithm of a number less than 1, subtract the number of ciphers between the decimal point and first significant figure from 9, writing — 10 after the mantissa.
Page 8 - The logarithm of any power of a number is equal to the logarithm of the number multiplied by the exponent of the power.
Page 8 - The logarithm of a quotient is equal to the logarithm of the dividend minus the logarithm of the divisor.
Page 74 - The sum of the angles of a spherical triangle is greater than two and less than six right angles ; that is, greater than 180° and less than 540°.
Page 57 - In any triangle, the square of the side opposite an acute angle is equal to the sum of the squares of the other two sides, minus twice the product of one of these sides and the projection of the other side upon it.
Page 58 - It is the outcome of a long experience of school teaching, and so is a thoroughly practical book. All others that we have in our eye are the works of men who have had considerable experience with senior and junior students at the universities, but have had little if any acquaintance with the poor creatures who are just stumbling over the threshold of Algebra. . . . Buy or borrow the book for yourselves and judge, or write a better.
Page 7 - The logarithm of a product is equal to the sum of the logarithms of its factors.
Page 76 - The sine of any middle part is equal to the product of the tangents of the Adjacent parts. RULE II. The sine of any middle part is equal to the product of the cosines of the opposite parts.