I posted this earlier today:

Question

I do not know how to find a single function of x or ø by using an identity. How do you find a single function using identities for a problem such as:

cos(3pi/4 - x)

But I think either I'm trying to find ø or I'm trying to find what x equals. I just sincerely do not know what to do with these problems.

Answer 1

Both Steve and I both told you what was wrong with the wording of the question.
http://www.jiskha.com/display.cgi?id=1480115359

Did you even look at the responses?

Answer 2

I suggest you post the problem exactly as it was given to you. If it's just part of an exercise set, include the instructions that preceded the section containing the problem.