If f(x)=∑n=0∞cnxnf(x) = \sum_{n=0}^{\infty} c_n x^nf(x)=∑n=0∞cnxn has radius of convergence R=3R=3R=3, what is the radius of convergence of f′(x)f'(x)f′(x)?
R=3R=3R=3
R=9R=9R=9
R=1R=1R=1
R=0R=0R=0