solve: sin^2 x + sin x cos x = 0
sin² x + sin x cos x = 0sin x ( sin x + cos x ) = 0sin x = 0 ; x 1 = k π ; k ∈ Zsin x + cos x = 0 / ²sin² x + 2 sin x cos x + cos² x = 02 sin x cos x + 1 =0sin ( 2 x ) = - 1x = 3π / 2 + 2 kπ / : 2x 2 = 3π / 4 + kπ ; k ∈ Z
