Question

A solid if formed by revolving around the curve y=x^(2/3)+1, 0 less than or equal to x less than or equal to 2.5, by revolving around the x axis. Estimate the volume of the solid by partitioning [0, 2.5] into five subintervals of equal length, slicing the solid with planes perpendicular to the x axis at the subintervals left endpoints, and constructing cylinders of height 0.5 based on the cross sections at these points.