8. (i) Solve, for \(0 \leqslant \theta < \pi\), the equation
$$\sin 3 \theta - \sqrt { 3 } \cos 3 \theta = 0$$
giving your answers in terms of \(\pi\).
(ii) Given that
$$4 \sin ^ { 2 } x + \cos x = 4 - k , \quad 0 \leqslant k \leqslant 3$$
- find \(\cos x\) in terms of \(k\).
- When \(k = 3\), find the values of \(x\) in the range \(0 \leqslant x < 360 ^ { \circ }\)