Calculus

If a region in the plane is revolved about a line, the resulting solid is a solid of revolution,
and the line is called the axis of revolution.

To see how to use the volume of a disk to find the volume of a general solid of revolution, consider a solid of revolution formed by revolving the plane region about the indicated axis.

V=

Here are examples that explain how this method works.

VolumeOfRevolution(sqrt(sin(x)),
0,0..π,'axis'='horizontal',
'distancefromaxis'=0,output=
animation)













This figure shows adding disks in the general solid, which is the basic concept of the disk method.
As divided terms are decreasing to zero, or subinterval n is increasing to infinity,
it makes the formula above.