Finding the tangent vector is easy. If we think of t as time, then the vector gives our position on C as a function of time. Thus, our velocity vector is always tangent to our path. But, we know that
so that means that at each of the N + 1 points, we have
This relationship is really just the differential form of the familiar equation ``distance = rate time''. Note that is really a displacement vector between the ith and i+1th points on the curve C and is the time it takes to get from the ith to the i+1th point. In general, we take a uniform step between points so that .