$\"\"$

Increasing / decreasing test :

If $\"\"$ on the interval, then $\"\"$ is increasing on the interval.

If $\"\"$ on the interval, then $\"\"$ is decreasing on the interval.

The function is $\"\"$ .

The critical points exist when $\"\"$ .

Equate $\"\"$ to zero :

$\"\"$

$\"\"$ and $\"\"$ and $\"\"$

$\"\"$ and $\"\"$ and $\"\"$ .

$\"\"$ and $\"\"$ and $\"\"$

The critical points are $\"\"$ , $\"\"$ and $\"\"$ .

$\"\"$

Consider the test intervals are $\"\"$ , $\"\"$ , $\"\"$ and $\"\"$ .

\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \

The function is increasing on the intervals $\"\"$ and $\"\"$ .

Therefore the function is increasing over the interval $\"\"$ .

$\"\"$

The function is increasing over the interval $\"\"$ .