Solution
= Solution
Termwise <differentiation> gives
$$
f\prime(z)=\sum_{n=1}^{\infty}n a_nz^{n-1}.
$$
The differentiated <series> has the same radius of convergence $R$.
= Solution
Termwise <differentiation> gives
$$
f\prime(z)=\sum_{n=1}^{\infty}n a_nz^{n-1}.
$$
The differentiated <series> has the same radius of convergence $R$.