The equations are
,
,
and
.
Find the volume of the solid generated by revolving the region about the
-axis.
The Volume of the solid solid generated by revolving the region about the
-axis, for the function
in the interval
is
.
Here
and
.
The volume of the solid is
.



Apply formula :
.





The volume of the solid is
.
The center of mass:
\Let
and
be continuous functions such that
on
, and consider the planar lamina of uniform density
bounded by the graphs of
and
.
The moments about the
-axis and
-axis are
.
.
The center of mass
is
and
, where
is the mass of the lamina.
Find the centroid of the region.
\Here
,
and
.
Find
.
Substitute
,
and
in
.


Substitute
in
.
.
Find
.
Substitute
,
and
in
.





.
Find the center of mass
.
The center of mass
is
and
, where
is the mass of the lamina.
Substitute
,
and
in
.


Apply formula :
.


.
Substitute
and in
in
.
.
Substitute
and
.

The centroid of the solid is
.
The volume of the solid is
and centroid is
.