Question

How do you know if a limit is equal to positive or negative infinity?

Answer 1

Well it obviously depends on what the function is

Answer 2

i know that. when the limit is infinity how do you know if its positive or negative

Answer 3

do you understand my question?

Answer 4

Use test values

Answer 5

ill give you an example

Answer 6

And it helps to look at the graph as well

Answer 7

find the limit as x approaches -5 from left of 1/x+5

Answer 8

why is the answer negative infinity?

Answer 9

\[\lim_{x \rightarrow -5^-} 1/(x+5)\]

Answer 10

yes

Answer 11

okay, do you know what an asymptote is?

Answer 12

yes

Answer 13

okay, there will be a vertical asymptote at x = -5, right?

Answer 14

yeah

Answer 15

This is very important, as x approaches -5 from the left, for example, at -5.0001, y = -10000

Answer 16

im sorry but i dont get how this relates to my question