(i) Express the equation \(2 \cos^2 \theta = \tan^2 \theta\) as a quadratic equation in \(\cos^2 \theta\).

(ii) Solve the equation \(2 \cos^2 \theta = \tan^2 \theta\) for \(0 \leq \theta \leq \pi\), giving solutions in terms of \(\pi\).