$\"\"$

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 denominator: 1 + 3 = 4)

$\"\"$ (Cancel common terms)

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

$\"\"$ (Add: 1 + 243 = 244) $\"\"$

The value of $\"\"$ .