# How do you write an nth term rule for #a_2=-20# and #a_4=-5#?

##### 1 Answer

Jan 11, 2017

#### Explanation:

Although it is not specifically mentioned as the question is framed under "Geometric Series", it is assumed to be so.

In a geometric series if firs term is

the

As

**.................(1)**

**.................(2)**

Dividing **(2)** by **(1)**, we get

Hence

If

and if