A treatise on special or elementary geometry (1877)
Olney, Edward, 1827-1887, Olney, Edward, 1827-1887. Elements of trigonometry, plane and spherical · New York : Sheldon · leaf 362
ing that tan and cotare + when sin and cos have like signs, and — whenthey have unlike, and that cos and sec have likesigns, as also sin and cosec, or, more simply, that 1 Cin = —, cot = :—, sec = —, and cosec = cos tan cos sm the student cannot fail to know the sign of a func-tion at a glance. It… … Fig. 6. angles terminating in the other quadrants, but Uco are -f- in each quadrant * This is a convenient elliptical form foriBt quadrant, etc. an angle whose measuring; arc terminates in the 10 PLANE TRIGONOMETRY. ScH. 2.—The signs of functions of angles greater than 360* are readily deter-mined…
Geometry · Trigonometry
Internet Archive · California Digital Library · Public Domain Mark 1.0. Free to use for anything.
![An illustration from Divina proportione : opera a tutti glingegni perspicaci e curiosi necessaria oue ciascun studioso di philosophia: prospettiua pictura sculptura: architectura: musica: e altre mathematice: suavissima: sotile: e admirabile doctrina consequira: e delecterassi: co[n] varie questione de secretissima scientia (1509)](https://img.insideoutlibrary.com/img/200/ia-divinaproportion00paci-117-316.webp)
