$\"\"$

\

The sum of a geometric series is $\"\"$ .

\

Where $\"\"$ is first term and r is common ratio.

\

$\"\"$ (Substitute $\"\"$ )

\

$\"\"$ (Product of two same signs is positive)

\

$\"\"$ (Add: $\"\"$ ) $\"\"$

\

$\"\"$ (Evaluate powers: $\"\"$ )

\

$\"\"$ (Add: $\"\"$ )

\

$\"\"$ (Multiply by $\"\"$ , and reciprocal of $\"\"$ )

\

$\"\"$ (Multiply: $\"\"$ ) $\"\"$

\

The value of $\"\"$ .