(i) Use de Moivre's theorem to show that
\(\sec 6 \theta=\frac{\sec ^{6} \theta}{32-48 \sec ^{2} \theta+18 \sec ^{4} \theta-\sec ^{6} \theta}\)

(ii) Hence obtain the roots of the equation
\(3 x^{6}-36 x^{4}+96 x^{2}-64=0\)
in the form sec \(q \pi\), where \(q\) is rational.