# Math Help - Trig Identities Help

1. ## Trig Identities Help

I'm stuck on this question. I jest keep getting a really long answer that goes nowhere. THanks in advance.

2. Originally Posted by DaCoo911
I'm stuck on this question. I jest keep getting a really long answer that goes nowhere. THanks in advance.
LS $= \frac{\cos x - \sin x}{\cos x + \sin x}\cdot \frac{\cos x - \sin x}{\cos x - \sin x} = \frac{\cos^2 x - 2 \sin x \cos x + \sin^2 x}{\cos^2 x-\sin^2 x} = \frac{1 - \sin 2x}{\cos 2x}$

$=\frac{1}{\cos 2x} - \frac{\sin2x}{\cos 2x} =$ RS