(adsbygoogle = window.adsbygoogle || []).push({}); A little push on this trig identity plz

[tex] \tan^2(x)= \frac {1-\cos(2x)} {1+cos(2x)} [/tex]

I need a little push I know from my other post that [tex] \cos(2x)=\cos^2 (x) - \sin^2 (x) [/tex] (can someone explain why?)

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: A little push on this trig identity

**Physics Forums | Science Articles, Homework Help, Discussion**