Can someone help me with this problems?
1. (cos^2 (pi/2 - x))/cos x. I have no idea how to solve this one
2. tan^2 x /sec^2 x . Could this one be -1/sec^2 x ?
3. 1/(tan^2 x + 1)
4. tan x - (sec^2 x )/ tan x. I have -1/tan x