Wentworth, G. A. (George Albert), 1835-1906 · Boston, Ginn & company · leaf 33
40°) areequal to the functions of 40°. SECTION XXIVEXTENSION OF FORMULAS The Formulas [1], [2], [3] established for acute angles onpp. 13, 14 hold true for all angles. Thus, in each quadrant MP2 + OM2 = OP2. Therefore, sin2 x -f cos2 x = 1. [1] We have in each quadrant fromthe similar triangles… … FIG. 44 GONIOMETRY 45 That is, tanx = ^n-^. r2-| COS X L J sin x x csc x = 11 cos x x sec x = 1 v • [3] tan x x cot x = 1J Formulas [l]-[3] enable us, from a given value of onefunction, to find the absolute values of the other five func-tions, and also the sign of the reciprocal function. But…
Trigonometry · Surveying · Navigation
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
