Step 1:
\The integral expression is on interval
.
The expression is
Consider .
Using summation theorem :
\If is integral on
, then
.
Where ,
and
.
The integral expression is .
Step 2:
\Here and
.
Substitute in
.
.
.
Step 3:
\substitute values from 1 to 4.
Step 4:
\ using mid point theorem Area =.
.
Solution:
\Area of the function is .