# Thread: limit with products of n and e

1. ## limit with products of n and e

find the limit of $n^2*e^{-n}$ as n approaches infinity

I just dont see how to do limits of more complex things. I can take each part by itself, find its limit and multiply them by algebra rules of limits. But n^2 = infinity and e^-n = 0. That does not work. L'Hop rule does not work either.

I am really confused on how to do limits.

2. Hello.

Originally Posted by diroga
find the limit of n^2*e^{-n} as n approaches infinity

I just dont see how to do limits of more complex things. I can take each part by itself, find its limit and multiply them by algebra rules of limits. But n^2 = infinity and e^-n = 0. That does not work. L'Hop rule does not work either.

I am really confused on how to do limits.
Of course L'Hospital works perfectly.

$n^2*e^{-n} = \frac{n^2}{e^n}$

Using L'Hospital leeds to

$lim \frac{n^2}{e^n} = lim \frac{2n}{e^n} = lim \frac{2}{e^n}$

Can you see it now?

Regards
Rapha

3. :-/

yeah... 0

thx.