$\"\"$

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

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

Apply alternative formula for sum of a geometric series $\"\"$ .

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

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

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

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

$\"\"$ (Divide: $\"\"$ ) $\"\"$

The value of $\"\"$ .