SOLUTION: I need to prove this identity tan^2theta-sin^2theta = tan^2thetasin^2theta

Algebra ->  Trigonometry-basics -> SOLUTION: I need to prove this identity tan^2theta-sin^2theta = tan^2thetasin^2theta      Log On


   

Question 714760: I need to prove this identity
tan^2theta-sin^2theta = tan^2thetasin^2theta
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
On the left side we can say (sin^2)/(cos^2)-sin^2
=sin^2/cos^2-(sin^2*cos^2)/cos^2
=(sin^2 *(1-cos^2))/cos^2
=%28%28sin%5E2%28theta%29%29%2F%28cos%5E2%28theta%29%29%29%281-cos%5E2%28theta%29%29

To finish this, use cos%5E2%28theta%29%2Bsin%5E2%28theta%29=1 in the form of 1-cos%5E2%28theta%29=sin%5E2%28theta%29, and perform the substitution into that last step above.