Math, Mathematics, Science, Numerical Analysis, Integration.
the end of the first trapezoid, we add it’s width to our x value. Hence, each time we cross a trapezoid , we have to add a h with the a. So, to reach the r-th point on x axis(r-th x value) we have to add h , r-times with our x_0. As you can see each shape is a trapezoid. Hence we just need to find