(i)[3]
Show that $\dfrac{\sin\theta}{\sin\theta + \cos\theta} + \dfrac{\cos\theta}{\sin\theta - \cos\theta} = \dfrac{1}{\sin^2\theta - \cos^2\theta}$.
(ii)[4]
Hence solve the equation $\dfrac{\sin\theta}{\sin\theta + \cos\theta} + \dfrac{\cos\theta}{\sin\theta - \cos\theta} = 3$, for $0^\circ \leq \theta \leq 360^\circ$.