The function \(f\) is defined by \(f(x)=3\sin^2x-2\cos x\) for \(2\le x\le4\), where \(x\) is in radians.

(a) Find the \(x\)-coordinate of the stationary point on the curve \(y=f(x)\).

(b) Solve the equation \(f(x)=1-3\cos x\).