What have you tried here?
Maybe start by making a common denominator on the LHS.
Determine solutions for:
(cosx)/(1 + sinx) + (1 + sinx)/(cosx) = 2 , in the interval x E [-2p,2p]
The answer taken from the back of the book is: -2p, 0, 2p
If someone could explain how to solve this equation, I'd really appreciate it! Thanks in advance