$\"\"$

The function is $\"\"$ .

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

The function is $\"\"$ on $\"\"$ .

Therefore, the function is decreasing on $\"\"$ .

Thus, $\"\"$ .

$\"\"$ is decreasing on $\"\"$ and therfore $\"\"$ .

$\"\"$

$\"\"$ is decreasing on $\"\"$ and therfore $\"\"$ .