Trigonometric Equation

there are 3 solutions to this equation,
x= 0, ∩/2 , -∩/2

there are 2 solutions:
x= (2n-1)∩/2 ; here n is any integer..
n∩ ; here n is an multiple of 2.

i am sure of my answer !!!....i donot get any logic behind the answer of saurabh 19!!!

1stly the qsn setter should've posted the interval in which he requires the ans....2ndly what saurabh has done is wrong, and no arguments pls, coz simple logic settles this....this eqn is basically equal to
cos^5x=(1+sin^2x)
(whenever cos x ≠0), draw the graph of both L.H.S and R.H.s to settle this, apart from that cosx=0 always settles this!