(i)[2]
Demonstrate that the equation $3\cos^4\theta + 4\sin^2\theta - 3 = 0$ may be rewritten as $3x^2 - 4x + 1 = 0$, with $x = \cos^2\theta$.
(ii)[5]
Hence, determine the solutions of $3\cos^4\theta + 4\sin^2\theta - 3 = 0$ for $0^\circ \leq \theta \leq 180^\circ$.