If f(x)=∑anxnf(x) = \sum a_n x^nf(x)=∑anxn has radius R=2R=2R=2, what is the radius of convergence of ∑anx3n\sum a_n x^{3n}∑anx3n?
23\sqrt[3]{2}32
222
23=82^3=823=8
1/21/21/2