SOLUTION: I need to prove the identity. (cos 2x) / (1 - tan^2 x) = cos^2 x

Algebra ->  Trigonometry-basics -> SOLUTION: I need to prove the identity. (cos 2x) / (1 - tan^2 x) = cos^2 x      Log On


   

Question 929094: I need to prove the identity.
(cos 2x) / (1 - tan^2 x) = cos^2 x
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
prove the identity.
(cos 2x) / (1 - tan^2 x) = cos^2 x
---------------
Multiply both sides by (1-tan^2(x)) to get:
cos(2x) = cos^2(x) - sin^2(x)
---
cos(2x) = cos(2x)
------------------
Cheers,
Stan H.
------------------