(sec(x) - tan(x))2 = 1 - sin(x)/ 1 sin(x)

Please learn to use parentheses properly. And also note that you can not cut and paste equations from other applications into this site - it drops some of the characters,( such as plus signs)

I think what you meant to write is this:

(sec(x) - tan(x))^2 = (1 -sin(x))/(1+sin(x))

Start by converting the sec(x) and tan(x) functions into theire sin(x) and cos(x) equivalents. The left hand side becomes


(\frac 1 {\cos(x)} - \frac {\sin(x)}{\cos(x)} )^2 = \frac {(1-\sin(x))^2}{\cos^2x} = \frac {(1-\sin(x))^2}{1-\sin^2x} = .....


I'm sure you can take it from here.