# Math Help - Radius of Convergence

1. ## Radius of Convergence

Find all the values of such that the given series would converge.

∑ [(−1)^n*x^n] / [5^n*(n^2+8)]
n=1

I need this in interval notation, please help!

2. Originally Posted by Del
Find all the values of such that the given series would converge.

∑ [(−1)^n*x^n] / [5^n*(n^2+8)]
n=1

I need this in interval notation, please help!
Where are you stuck? What have you tried?

3. I don't even know where to start.

4. Originally Posted by Del
I don't even know where to start.
apply the ratio test, or the root test, if you can handle it. then solve for what x needs to be

can you continue?