$\"\"$

Integral Test :

If $\"\"$ is positive, continuous and decreasing for $\"\"$ and $\"\"$ then $\"\"$ and $\"\"$ either both converge or both diverge.

$\"\"$

The integral series is $\"\"$ .

Let the function be $\"\"$ .

$\"\"$ is not positive for $\"\"$ .

Therefore, the integral test is not applicable for the series.

$\"\"$

$\"\"$ is not positive for $\"\"$ .