(a)[2]
Write $u$ in the form $r(\cos \theta + i\sin \theta)$, where $r > 0$ and $-\pi < \theta \leq \pi$. State the exact values of $r$ and $\theta$.
(b)[2]
The complex number $v$ is given by $v = 5\left(\cos \frac{\pi}{6} + i\sin \frac{\pi}{6}\right)$. Write the complex number $\frac{v}{u}$ in the form $re^{i\theta}$ where $r > 0$ and $-\pi < \theta \leq \pi$.