The function is
.
Observe the graph :
\The interval is
.
Consider
.
Differentiate with respective to
.

at
.
Surface area:
\Let
is a continuous derivative on the interval
.
The surface area is
,
is the distance between
and the axis of revolution.
Where
is
and
.
Substitute
and
in
.
.
The surface area is
.
Consider
.
Differentiate with respective to
.


.
If
then
.
If
then
.
Substitute the corresponding values in
.






.
.
.