Hello, tallguywhoplaysguitar!
There must be a typo.
As written, the statement is not an identity.
We need these two identities:
. .
. .
Prove: .
We have: .
Apparently I'm supposed to put these questions in this subforum, so here it goes.
I've tried this problem several times in different ways and never managed to prove it.
Prove:
--sin2x--= cot2x
1-cos2x
These are double angles, not squared.
Thanks for helping.