What's the s-axis? And s(0)? If s is your time in seconds, is the function s returning time based on acceleration, distance, velocity, what?

I'm assuming your distance at time 0 is 1. In which case you just take the integral of V(t) and your constant of integration becomes 1.

D(t) = x^3 + x^2 + 1

Edit: Well this seems to explain it better than my feeble mind.