Use the graph of f to find the limit How can I use the graph of f to find the limit?




$\displaystyle \lim_{x \to 1^−}f(x)$ 
$\displaystyle \lim_{x\to 1^+}f (x)$


I am not sure where to start
Look to the graph! 

When you come from numbers smaller than 1, the function gets bigger and bigger, so it goes to $\infty$. Therefore we have $\lim_{x\rightarrow1^{-}} = +\infty$.

When you come from numbers smaller than 1, the function gets smaller and smaller, so it goes to $-\infty$. Therefore we have $\lim_{x\rightarrow1^{+}} = -\infty$.

Also, make sure to get the right notation. The post has been edited, but it wasn't correct before the edit.
Just looking at the graph we have:
$$
\lim_{x\to 1^-}f(x)=+\infty, \quad \lim_{x\to 1^+}f(x)=-\infty.
$$