Hi there, I was wondering if someone would be able to help me solve this equation :

cos(x+TT/6) + cos(x-TT/4) = 0

It's driving me insane. I use compound angle theorem to expand the components and end up with:

I then tried squaring both sides and using trig identities to put everything in terms of . And got something that I wont waste your time with. Please help!