Find all values of x in the interval [0, 2π] that satisfy the equation.

3 sin (2x) = 3 cos (x)

3 sin (2 x) = 3 cos x

3 · 2 sin x cos x - 3 cos x = 0

6 sin x cos x - 3 cos x = 0 / : 3

2 sin x cos x - cos x = 0

cos x (2 sin x - 1)

cos x = 0,

x 1 = π/2, x 2 = 3π/2;

2 sin x - 1 = 0

2 sin x = 1

sin x = 1/2

x 3 = π/6, x 4 = 5π/6.