Geometric Series is basically the sum of all terms in the sequence.
You can call it the counterpart of the Arithmetic Series.
The formula for it is Sn = t1 (1 - r^n) / 1 - r [ S (sub n) = t (sub 1) times 1 - r^2 over 1 - r
Sn = the sum
r = common ratio
t1 = first term
n = number of terms.