Step 1 :

The geometric series $\"\"$

is convergent if $\"\"$ and its sum is

$\"\"$

If $\"\"$ , the geometric series is divergent.

Step 2 :

The expression is $\"\"$

Rewrite the expression.

$\"\"$

The above series is geometric series with $\"\"$ and $\"\"$ .

Observe that $\"\"$ .

Hence, the geometric series is convergent.

The sum is

$\"\"$

Solution : $\"\"$