$\"\"$

The function is $\"\"$ .

Apply derivative on each side with respect to $\"\"$ .

$\"\"$

$\"\"$ .

$\"\"$

Graph the functions $\"\"$ and $\"\"$ .

$\"\"$ .

The function does not have a zero slope at any point therefore the graph of its derivative never intersects the $\"\"$ -axis.

$\"\"$

$\"\"$ .

Graph the functions $\"\"$ and $\"\"$ .

$\"\"$ .

The graph of its derivative never intersects the $\"\"$ -axis.