Premise (Relates heavily to Riemann Sums):
Imagine you have a car travelling a displacement , where is a specific time on his journey. He gradually speeds up, steadies out and slows down. His velocity at any one time is .
A tiny change in displacement (I.E. ) can be gotten using a tiny change in time (I.E. ) multiplied by the velocity at that point in time . Rearranged you get .
Cue the idea of Integration