here are the problems I am having problem with... no pun intended...

(1 + tan^2X)(1 + cos2x) = 2 (prove identity)

(1 + sinA - cos2A) / (cosA + sin2A) = tanA

and Solve the equation for 0 < or = x < or = 2pi

cosx + cos2x + 2sin^2x = 0

your help is much appreciated!