Use the values 1,1.5,2,4,5 to subdivide the interval [1,5] into subintervals. Using these subintervals and the right end-points of each subinterval as the sample points, compute a Riemann sum for the integral [1,5] ∫ 2*x^2*ⅆx.

I don't know how to to do this. I try doing it like this:

(4/5)*(f(1)+f(1.5)+f(2)+f(4)) and I get 64.32

The online homework system says its wrong, and I don't know any other way to do it.