Solve sin 4x - cos 2x = 0.

Sin 4 x - cos 2 x = 0

2 sin 2 x cos 2 x - cos 2 x = 0

cos 2 x (2 sin 2 x - 1) = 0

cos 2 x = 0

2 x = π/2 + nπ / : 2

x 1 = π/4 + nπ/2, n ∈ Z

2 sin 2 x - 1 = 0

2 sin 2 x = 1

sin 2 x = 1/2

2 x = π/6 + 2 nπ

2 x = 5π/6 + 2 nπ

x 2 = π/12 + nπ

x 3 = 5π/12 + nπ, n ∈ Z