Question

Determine if the sequence below is arithmetic or geometric and determine the

common difference / ratio in simplest form.
4, 2, 1, ...

Answer 1

This is a geometric sequence, and the common difference/ratio is 0.5

Explanation:

The difference between 4 and 2 is * 0.5, or 1/2, which is the same between 2 and 1. This means that we are dividing.

Remember that arithmetic means plus or minus, while geometric means multiplication or division. Because we are dividing, this is a geometric sequence.

The common difference/ratio in this is divided by 2, which is the same as being multiplied by 0.5.