I have issue solving this equation.
So I wrote $$\sin3x= 3\sin x-4\sin^3x$$ and $$\sin2x = 2\sin x\cos x$$
So we have $$3\sin x-4\sin^3x-(2\sin x\cos x)-\sin x = 0$$
But now I have $$\sin x$$ and $$\cos x$$ as unknown, and I don't know how to finish this.