Bob BrownMath 252 Calculus 2 Chapter 7, Section 2 Completed3CCBC DundalkWhen you determine the volume of a solid of revolution using the disk method, your diagram will resemble one of the two following diagrams. Note that with the disk method, the representative rectangle that you draw will be perpendicularto the axis of revolution.
The disk method can be generalized to a method called the washer method. Before we discuss the washer method, we must review the definition of an annulus.Def.: An annulus is a circular region in the plane that has had a smaller, inner, centered, circular region removed.What is the area of an annulus?