If $lim_{n\rightarrow\infty} \frac{a_n}{b_n} = c$ and $c>0$, then ${a_n}$ and ${b_n}$ have the same convergence behavior (i.e. if one converges the other converges and if one diverges then the other also diverges).
But what if $c$ is less than $0$? Does that mean no conclusions can be drawn? And what if $c$ is equal to zero?
Any help is appreciated.