Observe the graph :

The function is $\"\"$ .

$\"\"$ is decreasing on $\"\"$ , increasing on $\"\"$ and decreasing on $\"\"$ .

Support numerically :

Construct the table of values by using the $\"\"$ -values in each interval.

The interval $\"\"$ :

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

Observe the above table, $\"\"$ is decreasing on $\"\"$ .

The interval $\"\"$ :

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

Observe the above table, $\"\"$ is increasing on $\"\"$ .

The interval $\"\"$ :

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

Observe the above table, $\"\"$ is decreasing on $\"\"$ .

$\"\"$ is decreasing on $\"\"$ , increasing on $\"\"$ and decreasing on $\"\"$ .