The function is
,
.
Area of the region is
.
Where
and
.
Let number of subintervals be 

.
Substitute
in
.






Apply summation formula
.
Apply summation formula
.




As
, then
.

.
Area of the region is between
and
-axis is
.
Graph the region:
\Area of the region is
sq-units.
Area of the region is
sq-units.