Answer
$s(t)= \sin (2t)-3$
Work Step by Step
Since, we know that the derivative of velocity is acceleration, so we have $v(t)=2 \cos 2t+C$
Given:$v(0)=2$
so, $2=2 \cos 2(0)+C $ or, $C=0$
This implies, $v(t)=2 \cos 2t$
Since, we know that the derivative of position $s(t)$ is velocity, so $s(t)=\sin 2t+C'$
we have $s(0)=-3$
and $-3=\sin 2(0)+C' $ or, $C'=-3$
Hence, $s(t)= \sin (2t)-3$