# Math Help - radius of convergence

How do you find the radius of convergence for power series like the following:

$\sum_{n=1}^\infty (1/n!)*(z-1+i)^{2n}$

$\sum_{n=0}^\infty z^{2n+1}$

$\sum_{n=1}^\infty (1/n!)*(z-1+i)^{2n}$
Hint: Use the fact that $(n!)^{1/n} \to \infty$ and now use the root test.
$\sum_{n=0}^\infty z^{2n+1}$