(1) (sinx)^4 - (sinx)^2 + (cosx)^2
=(1-cos2x)^2/4 + cos2x
= [ 1 - 2 cos2x + (cos2x)^2 + 4 cos2x ] / 4
= ( 1 + cos2x )^2 /4
= [ ( 1 + cos2x ) / 2 ]^2
= (cosx)^4
(1) (sinx)^4 - (sinx)^2 + (cosx)^2
=(1-cos2x)^2/4 + cos2x
= [ 1 - 2 cos2x + (cos2x)^2 + 4 cos2x ] / 4
= ( 1 + cos2x )^2 /4
= [ ( 1 + cos2x ) / 2 ]^2
= (cosx)^4