6 The angle \(x\) radians satisfies the equation
$$\cos \left( 2 x + \frac { \pi } { 6 } \right) = \frac { 1 } { \sqrt { 2 } }$$
- Find the general solution of this equation, giving the roots as exact values in terms of \(\pi\).
- Find the number of roots of the equation which lie between 0 and \(2 \pi\).