Finding limit of fraction with square roots: $\lim_{r\to 9} \frac {\sqrt{r}} {(r-9)^4}$ I have been looking at this for five minutes, no clue what to do.
$$\lim_{r\to 9} \frac {\sqrt{r}} {(r-9)^4}$$

The limit is $+\infty$ because the numerator approaches a positive number and the denominator approaches $0$ from above.  Sometimes one says the limit "doesn't exist" when one means there is no real number that is the limit, so you could put it that way.
