(i) Express the equation \(3 \sin \theta = \cos \theta\) in the form \(\tan \theta = k\) and solve the equation for \(0^\circ < \theta < 180^\circ\).

(ii) Solve the equation \(3 \sin^2 2x = \cos^2 2x\) for \(0^\circ < x < 180^\circ\).