Question

simplify cox^2x-cos^4x

Answer 1

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

= cos^2 x (sin^2 x)
= (sinxcosx)^2
= [ (1/2)sin (2x) ]^2
= (1/4) (sin^2 (2x) )

debatable whether that is more "simplified" than the original.