(i) Show that the equation \(\frac{4 \cos \theta}{\tan \theta} + 15 = 0\) can be expressed as \(4 \sin^2 \theta - 15 \sin \theta - 4 = 0\).

(ii) Hence solve the equation \(\frac{4 \cos \theta}{\tan \theta} + 15 = 0\) for \(0^\circ \leq \theta \leq 360^\circ\).