# Geometric progression

Keywords: Geometric progression

Geometric sequence, is a sequence of numbers where each term after the first is found by multiplying the previous one by a fixed, non-zero number called the common ratio.
For example: 1, 2, 4,.....,32,64,128,...

${a}_{1},{a}_{2},{a}_{3},...,{a}_{n-1},{a}_{n},{a}_{n+1},...$

n-th term of the sequence:

${a}_{n}={a}_{1}\cdot {q}^{n-1}$

The sum of the first n terms: