1: The exponential can be ignored first, the fraction is a ratio of
polynomials and it is of the type
.
What should one do? The "+1" and "−1" parts can be ignored when n is large,
what is left is
The easier way is to determine leading terms in the fraction and factor them out, even easier is to cancel the leading term.
An alternative would be to pull the exponential out of the limit and apply
l'Hospital's rule to the
resulting limit of the type .