# Question #d30b9

Aug 24, 2016

Most versions on an epsilon-delta definition require $\delta > 0$.

#### Explanation:

Perhaps the definition you're working with is something like:

${\lim}_{x \rightarrow {a}^{-}} f \left(x\right) = - \infty$ if and only if, for every $B$, there is a $\delta > 0$ such that for every $x$, if $a - \delta < x < a$, then $f \left(x\right) < B$.

This allows for the possibility that $B$ is a positive number, in which case $- \frac{1}{B}$ would be negative..

Without knowing exactly what definition you're working with, I can only suggest that that's the problem.