A curve has equation \(y = 2 + 3 \, \sin \frac{1}{2}x\) for \(0 \leq x \leq 4\pi\).

(a) State greatest and least values of \(y\). [2]

(b) Sketch the curve. [2]

(c) State the number of solutions of the equation \(2 + 3 \, \sin \frac{1}{2}x = 5 - 2x\) for \(0 \leq x \leq 4\pi\). [1]