Answer
$s=t+\sin t+4$
Work Step by Step
We need to find the anti-derivative for $\dfrac{ds}{dx}=1+\cos t$
Thus, we have $s=t+\sin t+C$
Apply the initial condition $s(0)=4$ in the above equation to solve for $C$.
we get: $4=0+\sin 0+C \implies C=4$
Hence, $s=t+\sin t+4$