# What are the values of a1 and r of the geometric series? 2 – 2 + 2 – 2 + 2

Geometric series is a series where the ratio between a term and the term preceding it is always the same.

## Answer: The values of a_{1} and r are 2 and -1 respectively.

Let us find the values of a_{1} and r.

**Explanation:**

The terms in the geometric series are 2, -2, 2, -2, ...

The first term is 2. So, a_{1} = 2

r is the common ratio.

Common Ratio = -2 / 2 = -1

So, r is -1