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## Calculus, all content (2017 edition)

### Unit 1: Lesson 19

Unbounded limits (vertical asymptotes)- Infinite limits intro
- Connecting limits at infinity notation and graph
- Infinite limits: graphical
- Analyzing unbounded limits: rational function
- Analyzing unbounded limits: mixed function
- Infinite limits: algebraic
- Visually determining vertical asymptotes (old)

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# Visually determining vertical asymptotes (old)

An old video where Sal identifies all the vertical asymptotes of a function given graphically. Created by Sal Khan.

## Video transcript

- [Instructor] Given the graph of y equals f of x pictured below, determine the equations of
all vertical asymptotes. Let's see what's going on here. So it looks like interesting
things are happening at x equals negative
four and x equals two. At x equals negative
four, as we approach it from the left the value of the function just becomes unbounded right over here. Looks like as we approach
x equals negative four from the left, the value of
our function goes to infinity. Likewise, as we approach
x equals negative four from the right, it looks like our, the value of our function
goes to infinity. So, I'd say that we definitely
have a vertical asymptote at x equals negative four. Now, let's look at x equals two. As we approach x equals two from the left, the value of our function once
again approaches infinity, or it becomes unbounded. Now, from the right, we
have an interesting thing. If we look at the limit from
the right right over here, it looks like we're
approaching a finite value. As we approach x equals
two from the right, it looks like we're approaching f of x is equal to negative four. But, just having a one-sided
limit that is unbounded, is enough to think about
this as a vertical asymptote. The function is not
defined right over here, and as we approach it from just one side, we are becoming unbounded. It looks like we're approaching infinity or negative infinity, so that by itself, this unbounded left hand limit,
or left-side limit by itself is enough to consider x equals
two a vertical asymptote. So, we can say that there's
a vertical asymptote at x equals negative
four and x equals two.