For the series ∑n=1∞n!2n\sum_{n=1}^{\infty} \frac{n!}{2^n}∑n=1∞2nn!, compute limn→∞an+1an\lim_{n \to \infty} \frac{a_{n+1}}{a_n}limn→∞anan+1 in the ratio test.
000
12\frac{1}{2}21
∞\infty∞
111