Geometric Series
A geometric series is a series whose related sequence is geometric. It results from adding the terms of a geometric sequence.
Example 1:
Finite geometric sequence : 
Related finite geometric series : 
Example 2:
Infinite geometric sequence : 2, 6, 18, 54, ···
Related infinite geometric series : 2 + 6 + 18 + 54 + ···
Written in sigma notation : 
