This document discusses calculating the volume of a solid of revolution using the washer method. It defines a solid of revolution as being created by revolving a region bounded by two functions, f(x) and g(x), around the x-axis. This creates a series of washers, where f(x) is the outer radius and g(x) is the inner radius. The volume formula for a single washer is given as π(r22 - r12)h. Taking the limit of many thin washers, the formula for finding the total volume using the washer method is given as the integral from a to b of π[f(x)2 - g(x)2]