find the limit of the following sequence or determine that the sequence diverges. { ( 1 - 20 / n ) ^ n }…

find the limit of the following sequence or determine that the sequence diverges. { ( 1 - 20 / n ) ^ n } select the correct choice below and, if necessary, fill in the answer box to complete your choice. a. the limit of the sequence is. (type an exact answer.) b. the sequence diverges.
Answer
Explanation:
Step1: Recall the limit formula
We know the well - known limit formula $\lim_{n\rightarrow\infty}(1 + \frac{a}{n})^n=e^{a}$. Here, our sequence is $a_n=(1-\frac{20}{n})^n$. Let $m=-n$ and $b = 20$. Then as $n\rightarrow\infty$, $m\rightarrow-\infty$. And $(1-\frac{20}{n})^n=\left(1+\frac{(- 20)}{n}\right)^n$.
Step2: Calculate the limit
By the formula $\lim_{n\rightarrow\infty}(1+\frac{a}{n})^n = e^{a}$, when $a=-20$, we have $\lim_{n\rightarrow\infty}(1-\frac{20}{n})^n=e^{-20}=\frac{1}{e^{20}}$.
Answer:
A. The limit of the sequence is $\frac{1}{e^{20}}$