Practice Demo

Find the limit if it exists. If the limit cannot be specified as a constant or infinity, enter $_DNE_$.
$$\lim_{z\to 4 }{\frac{-2}{20 - 9z+z^{2}}}$$

Preview your answer:


Hint 1: We can graph the function $_\frac{-2}{20 - 9z+z^{2}}_$ to see what happens near $_z=4_$:


From the graph, we can see that the left and right limits are different. Therefore,

$$\lim_{z\to 4 }{\frac{-2}{20 - 9z+z^{2}}} \text{ does not exist.} $$