Yes, but $\displaystyle \lim\text{ }a_n=0\implies \sum_{n=1}^{\infty}a_n<\infty$?
No, although in this case we know that since $\displaystyle \rho$ is real, the sum is actually equal to $\displaystyle e^\rho$. Should I write that down?
No, although in this case we know that since $\displaystyle \rho$ is real, the sum is actually equal to $\displaystyle e^\rho$. Should I write that down?
Thank you for your help!
That isn't how to do this. Try using the ratio test.