$\"\"$

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

Find $\"\"$ .

The general form of partial sum of $\"\"$ -terms $\"\"$ , where $\"\"$ .

$\"\"$

Substitute $\"\"$ and $\"\"$ in the general form.

$\"\"$

The value of $\"\"$ is $\"\"$ .

$\"\"$

The value of $\"\"$ is $\"\"$ .