Find an approximation to the area bounded by the graph of y = sin(x) and the x-axis from x = 0 to x = p.
The following LiveMath Notebook shows the steps you would follow in doing this problem. It is possible for you to change the various coefficients. View an animation to see how this can be done.

Why are the left-hand sums always equal to the right-hand sums?

What happens as you increase the value of n?