# Question #f639b

##### 2 Answers

Use the Ratio Test (it's usually a good idea whenever factorials are involved) to show that this series converges.

#### Explanation:

Let

We want to know whether the series

To apply the Ratio Test, we consider the sequence

This expression simplifies to:

It is well known that

By the Ratio Test, this is enough to imply that the series

See below.

#### Explanation:

Using the Stirling asymptotic formula

and from