If 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)=2f(0)=2f(0)=2, what is ana_nan?
1/n!1/n!1/n!
2/n!2/n!2/n!
1/(2n!)1/(2n!)1/(2n!)
2n/n!2^n/n!2n/n!