$\"\"$

\

The series is $\"\"$ .

\

Rewrite the series as $\"\"$ .

\

The series is in the form of geometric series.

\

Here the first term $\"\"$ and common ratio is $\"\"$ .

\

If the series is converges, then $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$ .

\

The series is converges when $\"\"$ .

\

$\"\"$

\

The sum of the series in geometric series is $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$ .

\

The sum of the series is $\"\"$ .

\

$\"\"$

\

Interval of convergence is $\"\"$ .

\

The sum of the series is $\"\"$ .