Question

Solve: sin^2 x + sin x cos x = 0

Answer 1

Sin² x + sin x cos x = 0
sin x ( sin x + cos x ) = 0
sin x = 0 ;  x 1 = k π ;  k ∈ Z
sin x + cos x  = 0  / ²
sin² x + 2 sin x cos x + cos² x = 0
2 sin x cos x + 1  =0
sin ( 2 x ) = - 1
x = 3π / 2 + 2 kπ     / : 2
x 2 = 3π / 4 + kπ ;  k ∈ Z