SOLUTION: How do I go about proving this identity?: {{{1+tan(x)tan(x/2)}}}{{{""=""}}}{{{sec(x)}}} I've been looking up sites and asking friends but I just don't understand this.

Algebra ->  Trigonometry-basics -> SOLUTION: How do I go about proving this identity?: {{{1+tan(x)tan(x/2)}}}{{{""=""}}}{{{sec(x)}}} I've been looking up sites and asking friends but I just don't understand this.      Log On


   

Question 1077073: How do I go about proving this identity?:
1%2Btan%28x%29tan%28x%2F2%29%22%22=%22%22sec%28x%29
I've been looking up sites and asking friends but I just don't understand this.
Answer by Edwin McCravy(20065) About Me  (Show Source):
You can put this solution on YOUR website!
1%2Btan%28x%29tan%28x%2F2%29%22%22=%22%22sec%28x%29

Are you familiar with this half-angle identity? 

tan%28x%2F2%29%22%22=%22%22%281-cos%28x%29%29%2Fsin%28x%29

That substitution makes it easy.  But if you still have 
trouble proving the identity after using that, tell me
about it in the thank-you note form below and
I'll get back to you by email. (No charge ever!)

Edwin