Are you really having trouble solving elementary trig equations?
But all the solutions of  are included in .
Therefore, the solution is: .
need values after using sum to product formula.
I used sum to product and get 2sin4xcosx=0
setting each factor to 0, 2sin4x=0 and cosx=0,
I have the answers in the book, but need to know how to get to the answers. x=0, pi/4, pi/2 etc. (adding [(npi)/4] each time.
thanks for the encouraging remarks! I'm having a lot of trouble understanding this stuff actually. And half way through the course now, and haven't seen the technique you use there (which is much easier than what I've been doing). Did I miss the rule about sin4x=0 can move to 4x=0+pi(n)??? When was I supposed to learn that? I know my professor has us jumping around the book, but I can't imagine I would forget that little rule..