The graphs of the inequalities are
,
,
and
.
Graph the inequalities
,
,
and
.

Observe the graph:
\
on
.
\
Moments and center of mass of a planar lamina:
\Let
and
be continuous functions such that f
on
, and consider the planar lamina of uniform density
bounded by the graphs of
and
.
The moments about the
-and
-axis are
.
.
The center of mass
is
and
, where
is the mass of the lamina.
Find the area of the region
.

.
Substitute
.
Apply derivative on each side with respect to
.


.
Substitute
and
.






Substitute
and
.






.
The area of the region is
.
Find
.








.
.
Find
.
Since the graph is symmetrical about the
-axis, center of mass lies on the axis of symmetry
.
The center of mass
is
and
.
Substitute
and
in
.
.
Substitute
and
in
.
.
The centroid of the region is
.
The centroid of the region is
.