How to solve sin(x/2) = 1 - cos x? I know you would use the half angle identity sin(x/2) = +-(√1 - cos x/2), just don't know what to do from there.

Answer 1

I would gather terms, solve for cos x/2, then solve for x/2, then solve for x. You will have more than one solution

Answer 2

cosx = 1 - 2sin^2 x/2

Now you have a quadratic in u=sin x/2

u = 1-(1-2u^2)