solve the trigonometric equation

3-3cosx=2 sin^2 x

= 3 - 3cos x - 2 (1 - cos^2 x)

= 2cos^2 x - 3cos x + 1

= (cos x - 1) (cosx - 1/2)

now cos x = 1 or cos x = 1/2

draw a graph we get = + ve values

hence ... 0,180,360 and 60,240, degrees in range x<2pi