5. (i) Given that \(\sin \theta = 2 - \sqrt { 2 }\), find the value of \(\cos ^ { 2 } \theta\) in the form \(a + b \sqrt { 2 }\) where \(a\) and \(b\) are integers.
(ii) Find, in terms of \(\pi\), all values of \(x\) in the interval \(0 \leq x < \pi\) for which $$\cos 3 x = \frac { \sqrt { 3 } } { 2 }$$