Let $y = y ( x )$ be the solution of the differential equation $\sin x \frac { d y } { d x } + y \cos x = 4 x , x \in ( 0 , \pi )$. If $y \left( \frac { \pi } { 2 } \right) = 0$, then $y \left( \frac { \pi } { 6 } \right)$ is equal to\\
(1) $- \frac { 4 } { 9 } \pi ^ { 2 }$\\
(2) $\frac { 4 } { 9 \sqrt { 3 } } \pi ^ { 2 }$\\
(3) $\frac { - 8 } { 9 \sqrt { 3 } } \pi ^ { 2 }$\\
(4) $- \frac { 8 } { 9 } \pi ^ { 2 }$