1. The problem statement, all variables and given/known data Constants a,b,c,d 2. Relevant equations a/((1-b*cos(x))^1) + c = cos(x+d)/(1-b*cos(x)), solve for x 3. The attempt at a solution I've tried many different forms and substutions to try to factor this puppy and get 2 solutions. The expanded equation, after using the cos sum identity, looks like p*cos(x)^2 + q*cos(x) + r*sin(x) + s*sin(x)*cos(x) = t I attempted to eliminate the equation by multiplying t by sin(x)^2+cos(x)^2 and finding some common terms but so far that hasn't helped. I've also trying substituting all the half and double angle identities I know and haven't been able to come up with anything. I know this doesn't show much work, but I have spent a lot of time on this, so any help is much appreciated!