A Treatise on Plane and Spherical Trigonometry

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Leach, Shewell & Sanborn, 1894 - Plane trigonometry - 193 pages
 

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Page 34 - In every plane triangle, the sum of two sides is to their difference as the tangent of half the sum of the angles opposite those sides is to the tangent of half their difference.
Page 100 - The logarithm of any power of a number is equal to the logarithm of the number multiplied by the exponent of the power.
Page 58 - 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°. (gr). If A'B'C' is the polar triangle of ABC...
Page 57 - Cot. D. 1". Tan. M. 40° 139° 130° 49° M.] Sin. D. 1".
Page iv - The foregoing method is based on the assumption that the differences of logarithms are proportional to the differences of their corresponding numbers, which, though not strictly accurate, is sufficiently exact for practical purposes.
Page 51 - ... cos a = cos b cos с + sin b sin с cos A ; (2) cos b = cos a cos с + sin a sin с cos в ; ^ A. (3) cos с = cos a cos b + sin a sin b cos C.
Page 100 - I. The logarithm of a product equals the sum of the logarithms of the factors.
Page 62 - Rules are . (1) The sine of the middle part equals the product of the tangents of the adjacent parts.
Page vii - In searching for the next less (or greater) logarithm, attention must be paid to the fact that the functions are found in different columns according as the angle is below or above 45°. If, for example, the next less logarithmic sine is found in the column with
Page 32 - In any triangle the square of any side is equal to the sum of the squares of the other two sides minus twice the product of these two sides and the cosine of their included angle.

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