posted by Aqib .
I presume you want to solve this equation for something. It would be easier if you actually wrote it with variables, coefficients, all that cool stuff.
Or is it just an identity you want to prove? If you want help, don't just toss trash over the transom.
Ahh. an identity
(1-cos)/(1+cos) * (1-cos)/(1-cos)
= (1 - 2cos + cos^2)/sin^2
= (1 - 2cos + 1 - sin^2)/sin^2
Take x=π/4. Things don't match.