The Disc Method
The Disc Method is best represented in the image below.
Animated Disc Image


To find the volume of a solid of revolution with the disc method, use one of the following. Notice the corresponding figures as well.

Horizontal axis of revolution
                             b
Volume = V = pi §  [R(x)]2 dx
                             a
Disc 1 gif


Vertical Axis of Revolution
                             d
Volume = V = pi §  [R(y)]2 dy
                             c

Disc 2 gif

Click Here for an example problem.