Hello, I am looking at the following series:

sum, n=1 to infinity

{n^3} / e^n

using the ratio test, we get to:

{(n+1)^3} / en^3

however I cannot understand the final step which goes to 1/e which less than 1, so proves convergency.

Can someone please show me how it goes from :

{(n+1)^3} / en^3

to

1/e

Thanks kindly.