Wentworth, G. A. (George Albert), 1835-1906 · Boston, Ginn & company · leaf 37
.* Hence, For every acute anglethere is an angle in each of thehigher quadrants whose functions,in absolute value, are equal tothose of this acute angle. Let Z A OP = x, Z POB = y;then x -f y = 90°, and the func-tions of x are equal to the co-named functions of y (Sect. V, p. 11) ; and ZAOQ (in… … sin (180° — x) = sinx. sin (90° + y) = cos y. cos (180° — x) = — cos X. cos (90° + y) = — sin y. tan (180° — x) = — tan x. tan (90° + y) = — cot y. cot (180° —x) = — cot X. cot (90° + y)= — tany. * In future, secants, cosecants, versed sines, and coversed sines will bedisregarded. Secants and…
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