The function is
and the interval is
.

Apply derivative with respect to x .
\
Apply the sum and difference rule of derivatives.
\
Apply the power rule:
.

To find the critical numbers of
, equate
to zero.

is not in the region
.
Critical point is not in the in the given region is
.
To find the absolute extreme of function in given region
, sketch the function .
Left end point
is minimum point over the interval
.
Right end point
is maximum point over the interval
.
Minimum point is
.
Maximum point is
.