Answer :
= 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
= 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