First time posting, hey guys!

I need urgent h/w help that's due tomorrow.

Here are the problems:

2cosxcscx - 4cosx - cscx + 2 (find all the answers in the intervals of 0 to 2pi)

5sin^23x + 8sin3x - 4

(i finally was able to factor this and then i don't know how to solve the equations from there)

sec^2xtan^2x + sec^2x = sec^4x

(verify identity i think)

Thanks!

LAST EDIT: i figured out the third one!