7. (a) Find, in the form \(y = \mathrm { f } ( x )\), the general solution of the equation $$\cos x \frac { \mathrm {~d} y } { \mathrm {~d} x } + y \sin x = 2 \cos ^ { 3 } x \sin x + 1 , \quad 0 < x < \frac { \pi } { 2 }$$ Given that \(y = 5 \sqrt { 2 }\) when \(x = \frac { \pi } { 4 }\)
(b) find the value of \(y\) when \(x = \frac { \pi } { 6 }\), giving your answer in the form \(a + b \sqrt { 3 }\), where \(a\) and \(b\) are rational numbers to be found.