Do you mean sec 0/(1 + sec 0) ?
On the right side,do you mean
(1 - cos 0)/sin^2 0?
You need to use parentheses to make your equations unambiguous.
establish identity
sec 0/1 + sec0 = 1 - cos0/sin^2 0
1 answer
sec 0/1 + sec0 = 1 - cos0/sin^2 0
1 answer