The power series f(x)=∑n=0∞anxnf(x) = \sum_{n=0}^{\infty} a_n x^nf(x)=∑n=0∞anxn satisfies f′(x)=f(x)f'(x) = f(x)f′(x)=f(x) and f(0)=1f(0) = 1f(0)=1. What is ana_nan?
111
1/n1/n1/n
1/n!1/n!1/n!
n!n!n!