Let y=y(x) be the solution of the differential equation sin x (d y)/(d x)+y cos x=4 x, x ∈(0, π). If y((π)/2)=0, then y((π)/6) is equal to:

Let $\displaystyle y=y(x)$ be the solution of the differential equation $$\sin x \frac{\mathrm{~d} y}{\mathrm{~d} x}+y \cos x=4 x, x \in(0, \pi) . \text { If } $$ $\displaystyle y\left(\frac{\pi}{2}\right)=0$, then $\displaystyle y\left(\frac{\pi}{6}\right)$ is equal to :