Math
posted by Jillian on .
Prove the identity.
sin² θ = tan² θ / 1 + tan² θ

I assume the right side is supposed to be tan² è /(1 + tan² è)
Start by rewriting
1 + tan^2 = (cos^2 + sin^2)/cos^2
= 1 /cos^2
so that
1/(1+tan^2) = cos^2
Therefore the right side becomes
(sin^2/cos^2)* cos^2 = sin^2 
how did 1 + tan^2 become cos^2 + sin ^2?

oh nevermind i got it thank you.