Approximate the area under the curve over the specified interval by using the indicated number of subintervals (or rectangles) and evaluating the function at the right-hand endpoints of the...

Approximate the area under the curve over the specified interval by using the indicated number of subintervals (or rectangles) and evaluating the function at theright-hand endpoints of the subintervals.

f(x) = 4x − x² from x = 1 to x = 3; 2 subintervals