In order to calculate the volume of a solid of revolution, you can
either use the `int` command implementing the formula above or
use the Maple procedure `RevInt` which sets up the integral for
you. Try the examples below to see the different types of output.

> Pi*int(f(x)^2,x=-2..2); > evalf(Pi*int(f(x)^2,x=-2..2)); > RevInt(f(x),x=-2..2); > value(RevInt(f(x),x=-2..2)); > evalf(RevInt(f(x),x=-2..2));

2015-11-15