The function is .
Apply derivative with respect to .
Product rule of derivative : .
Derivative formulae : and
.
To find the relative extrema of the function equate to zero.
and
.
can never be zero.
.
Substitute in
.
The critical point is .
Determine the relative extrema, using second derivative test.
\Differentiate with respect to .
Substitute in the above equation.
By the second derivative test, the function has a relative minimum at .
Relative minimum : .