(i) Prove the identity \(\left( \frac{1}{\cos \theta} - \tan \theta \right)^2 \equiv \frac{1 - \sin \theta}{1 + \sin \theta}\).

(ii) Hence solve the equation \(\left( \frac{1}{\cos \theta} - \tan \theta \right)^2 = \frac{1}{2}\), for \(0^\circ \leq \theta \leq 360^\circ\).