Question

Can anyone verify 1-tan^2(x/2) = (2cosx)/(1+cosx)?

Answer 1

\[\tan ^2\frac{x}{2}=\frac{1-\cos x}{1+\cos x}\]

Answer 2

Might try that substitution ans see where it leads.

Answer 3

I did that and now im stuck.

Answer 4

\[1=\frac{1+\cos x}{1+\cos x}\]

Answer 5

Make that substitution as well.

Answer 6

Where?

Answer 7

On the left side.

Answer 8

but i thought i had 1-cosx/1+cosx