$\"\"$

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

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

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

$\"\"$ (Subtract denominator: $\"\"$ ) $\"\"$

$\"\"$ (Evaluate power: $\"\"$ )

$\"\"$ (Subtract numerator: $\"\"$ )

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

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

The value of $\"\"$ .