# Thread: Double and Half Angles

1. ## Double and Half Angles

For use a double-angle or half-angle formula to simplify the equation and then find all solutions of the equation in the interval

x=_________pi

2. Well, then use it, hence $2\sin x\cos x+\cos x=\cos x(2\sin x+1)=0,$ from here $\cos x=0$ or $2\sin x+1=0.$ Each one can be easily solved, do it.