(a) It is given that

\(2+\cos\theta=x,\qquad 1\lt x\lt 3\)

and

\(2\operatorname{cosec}\theta=y,\qquad y\gt 2.\)

Find \(y\) in terms of \(x\).

(b) Solve the equation

\(3\cos\frac{\phi}{2}=\sqrt3\sin\frac{\phi}{2}\)

for

\(-4\pi\lt \phi\lt 4\pi.\)