Differential Equations

If $x=\operatorname{sint}$ and $y=\sin p t$, then the value of

\(\left(1-x^2\right) \frac{\mathrm{d}^2 y}{\mathrm{~d} x^2}-x \frac{\mathrm{~d} y}{\mathrm{~d} x}+\mathrm{p}^2 y=\)