Let me teach you some of the basics of a geometric series...
The difference between a sequence and a series is:
A geometric series is formed by multiplying each term by a constant.
Could also be written as:
The n-th term is equal to:
is the starting term, the first term (a = 1 in the example).
is the common ratio (r = 2 in the example).
You can determine with the following formula:
In series and sequences, the Sigma-sign is very important.
Now i do hope that's all...