(i) Show that the equation \(3 \cos^4 \theta + 4 \sin^2 \theta - 3 = 0\) can be expressed as \(3x^2 - 4x + 1 = 0\), where \(x = \cos^2 \theta\).

(ii) Hence solve the equation \(3 \cos^4 \theta + 4 \sin^2 \theta - 3 = 0\) for \(0^\circ \leq \theta \leq 180^\circ\).