The power series ∑anxn\sum a_n x^n∑anxn satisfies f′′(x)=f(x)f''(x) = f(x)f′′(x)=f(x) with f(0)=1,f′(0)=0f(0)=1, f'(0)=0f(0)=1,f′(0)=0. What is ana_nan?
1/n!1/n!1/n!
1/(2n)!1/(2n)!1/(2n)!
1/(2n+1)!1/(2n+1)!1/(2n+1)!
1/(n2)1/(n^2)1/(n2)