Figure 8.5.3(a) is a preliminary sketch of the region , a sketch sufficient to suggest that in cylindrical coordinates, the iteration-order is one of the simpler approaches, even though it requires expressing the outer (red) surface as , and the inner (green) surface as .
Figure 8.5.3(b) depicts the actual region whose volume is to be calculated.
|
Figure 8.5.3(a) Preliminary sketch
|
|
|
|
|
Figure 8.5.3(b) The region
|
|
|
|
|
|
The following iterated integral computes the volume of in cylindrical coordinates.
The Jacobian of the transformation , , is
= =
Since , the outer surface becomes , or . Similarly, the inner surface becomes , or . Since describes the lower plane, on that surface, while gives on the upper plane. Hence, the volume of can also be calculated via the iterated integral