Buktikan identitas trigonometri berikut. a. [tex] \frac{sin A}{1 cos A}[/tex] = [tex] \frac{1+cos -

A. (sinA) / (1 - cos A) x (1 + cos A) / (1 + cos A)
= (sin A (1 + cos A))/ (1 - cos² a)
= sin A (1 + cos A) / sin² A
= (1 + cos A) / sin A  (terbukti)
b. sin A + cos A cotan A = sin A + cos A x cos A/sin A
= sin A + cos²A/sin A
= sin ²A/sin A + cos²A/sin A
= (sin ²A + cos ²A) /sin A
= 1/ sin A
= cosec A  (terbukti)
c. cosec A + cotan A = 1 / sin A + cosA /sin A
= (1 + cos A) / sin A
= (1 + cos A) / sin A x (1- cosA) / (1 - cos A)
= (1 - cos²A) / (sin A (1 - cosA)
= sin² A / (sin A (1 - cos A))
= sin A / (1 - cos A)  (terbukti)

Source https://sebuahcatatan.live/as/catatanbrain/tugas/2174554