Let $y=y(x)$ be the solution of the differential equation $\sec x \frac{\mathrm{dy}}{\mathrm{dx}}-2 \mathrm{y}=2+3 \sin \mathrm{x}, \mathrm{x} \in\left(-\frac{\pi}{2}, \frac{\pi}{2}\right)$, $y(0)=-\frac{7}{4}$. Then $y\left(\frac{\pi}{6}\right)$ is equal to: