Question

Buktikan identitas trigonometri berikut. (sin x - cos x)² = 1 - 2 sin x cos x

Answer 1

Verified answer

(sin x - cos x)²
= sin²x + cos²x - 2 sin x cosx
=1 - 2 sin x cos x
(terbukti)

note: sin² x + cos² x= 1

Answer 2

(sinx-cosx)(sinx-cosx)
sin^2 x -2sinxcosx + cos^2 x

sin^2 x + cos^2 x = 1 (sifat trigono)
1-2 sin x cosx (terbukti)