sin² x (1+ cot² x) = 1

Materi Trigonometri

sin^2 x (1 + cot^2 x)
= sin^2 x + sin^2 x cot^2 x
(cot x = cos x / sin x)
= sin^2 x + cos^2 x
(sifat identitas)
= 1 (Terbukti)