20sinx - 4cosx - 13 = 0 : solvable? Is this equation solvable? I've been banging my head on it for the past half hour and don't know how to start. 20sinx - 4cosx - 13 = 0 Also, this started out as a physics question, but seeing as this is just math stuff now I thought I'd put it here. I know all the physics was done correctly, so this is how it should end up.