I'm looking at the following complex analysis problem.
Suppose that $f$ is analytic in $D := U(z_0,r)\setminus \bigcup_{n=1}^\infty \{z_n\}$, all the points $z_n$ are poles, and $z_n \to z_0$. Prove $f(D)$ is dense in $\mathbb{C}$.
I feel like I have to define some function and manipulate it somehow, but I haven't been able to come up with a function that works. Can you help?