4sin2Xcos2X

A) 1/2sin16X

B) cos8X

C) cos4X

D)2sin4X

determine whether the equation is an identity. if an identity prove it.

(sinx+cosx)^2=1

find all solutions in [0,2pi)

tanxsecx=squareroot of 2.

2sinxcosx+cosx=0

thank you so much in advanced!!!!!