posted by Kate .
Prove each identity:
b) cos^2x + 2sin^2x-1 = sin^2x
I also tried a question on my own:
tan^2x = (1 – cos^2x)/cos^2x
I know that the Pythagorean for that is sin^2x + cos^2x
That's all I could do.
substitute tan(θ) by sin(θ)/cos(θ) on the RHS and see what you get.