Question

What is common ratio versus common difference?

Answer 1

If we are given a sequence of the form:

$a_1,a_2,a_3,a_4...a_n,a_{n+1}$

The common ratio is the number that is obtained by dividing one term by the previous term and is constant for any pair of terms:

$r=\frac{a_{n+1}}{a_n}$

When a sequence has a common ratio it is called a geometric sequence.

A common difference is a number obtained by the difference between a term and the previous term:

$d=a_{n+1}-a_n$

A sequence with a common difference is called an arithmetic sequence.