Answer
$\frac{dy}{dt}=0$
Work Step by Step
Given $y=3\sin2x$ and $x=t^2+\pi$
On differentiating both sides:
$\frac{dy}{dt}=6\cos2x\frac{dx}{dt}$
$\frac{dx}{dt}=2t$
$\frac{dy}{dt}=6\cos(2(t^2+\pi))\times2t$
at $t=0$
$\frac{dy}{dt}=6\times0\cos2\pi$
$\frac{dy}{dt}=0$
