Imagine you have a secret. You tell 3 friends, who each tell 3 friends, who then tell another 3 friends. This is an example of a geometric series.
Geometric Series: 1 + 3 + 9 + 27, r = 3
|Sum of a Geometric Series|
The sum of the first n terms of a geometric series is found using the equation:
where r cannot be equal to 1.
Let's calculate the sum of the first 9 terms of our geometric series: