Question

1+Cos2A/Cos2A = Tan2A/TanA Prove the Identity

Answer 1

Are you sure this typed correctly?

\({{\cos^2A} \over {\cos^2A}} = 1\)

That would make your statement:

\( 2 = {{\tan^2A} \over {\tan A}} \)

and I'm not sure that is true.

Answer 2

hi this is what they gave us

Answer 3

This is what we have
Atthment

Answer 4

Okay. The identity you want to prove is

\(\large \displaystyle {{1-\cos(2A)} \over {\cos(2A)}} = {{\tan(2A)} \over {\tan A}}\)

That's a bit different and I am willing to believe it might be true.

Answer 5

Do you know any of the double angle identities? If not do you know any of the sum and difference identities?

Answer 6

Here is the sum and difference identities for cos (in compressed form):

\(\large \displaystyle \cos (\alpha \pm \beta) = \cos\alpha\cos\beta \mp \sin\alpha\sin\beta \)

So what can you conclude \( \large \cos (2A) \) equals?