Consider the power series $f(x) = \sum_{n=1}^{\infty} \frac{(-1)^n}{n} x^n$, which converges for $|x| < 1$. The alternating series $\sum_{n=1}^{\infty} \frac{(-1)^n}{n}$ converges by the alternating series test. By Abel's Theorem, what must be true?