Calculus AB : Connect Infinite Limits and Vertical/Horizontal Asymptotes

Study concepts, example questions & explanations for Calculus AB

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Example Questions

Example Question #11 : Connect Infinite Limits And Vertical/Horizontal Asymptotes

Evaluate 

Possible Answers:

Correct answer:

Explanation:

The equation  will have a horizontal asymptote .

We can find the horizontal asymptote by looking at the terms with the highest power.

The terms with the highest power here are  in the numerator and  in the denominator. These terms will "take over" the function as x approaches infinity. That means the limit will reach the ratio of the two terms.

The ratio is 

Example Question #12 : Connect Infinite Limits And Vertical/Horizontal Asymptotes

Find .

Possible Answers:

Correct answer:

Explanation:

First step for finding limits: evaluate the function at the limit.

 which is an Indeterminate Form.

This got us nowhere. However, since we have an indeterminate form, we can use L'Hopital's Rule (take the derivative of the top and bottom and the limit's value won't change).

This is something we can evaluate:

The value of this limit is .

Example Question #13 : Connect Infinite Limits And Vertical/Horizontal Asymptotes

Assume that a population of bunnies grows at a rate of  where  is the number of bunnies in the population at time . If the population begins with 14 bunnies, given unlimited time to grow, how many bunnies do you expect there to be in the population?

 

Note: No integration is required for this problem.

Possible Answers:

 The population will never stop growing.

Correct answer:

Explanation:

The equation given is a model of logistic growth. Note that one of the other common forms this equation might be given in is . What we want to know is what the population will be given unlimited time, or what  is.

Looking at the form of the derivative above, note that if we start with 14 bunnies, we get a positive derivative. This means that the population is increasing. As our function is continuous, the population will keep growing until the derivative hits 0. When does this occur?

In the above form, it should be more clear that the derivative is only 0 at  and . Thus, the population will keep growing, but never go above 350, because if it were to hit 350, the derivative would be 0 and growth would stop. (Alternatively, if the population were above 350, you can see the derivative would be negative and that the population would shrink back down to 350. Indeed, it wasn't necessary to tell you we started with 14 bunnies -- the limit will be the same for any positive starting value.)

Example Question #14 : Connect Infinite Limits And Vertical/Horizontal Asymptotes

The function  has a horizontal asymptote at y=0. What does the presence of the horizontal asymptote imply?

Possible Answers:

At  the function is undefined.

The function will produce only positive outputs.

The function is discontinuous at .

The limit of the function as x-values approach 0 tends to either positive or negative infinity.

None of the other answers.

Correct answer:

None of the other answers.

Explanation:

Unlike vertical asymptotes, horizontal asymptotes of certain functions may be crossed. In these cases, and in the case of the given function, the horizontal asymptote may be crossed and even have defined values laying on it (e.g.,  for the function provided).

What is meaningful about the horizontal asymptote in this example is that it suggests the behavior of the function at large magnitudes. The denominator will increase much faster than the numerator. That is to say that the  will grow exponentially larger the  in the numerator such that, at large values (both positive and negative), the function will output y-values tending toward .

Example Question #15 : Connect Infinite Limits And Vertical/Horizontal Asymptotes

Screen shot 2020 09 04 at 10.13.07 am

Of the following functions, which most likely represents the sample data above?

Possible Answers:

Correct answer:

Explanation:

Observation of the data points shows that there is a sharp increase and decrease on either side of a particular x-value. This type of behavior is observed when there is a vertical asymptote. An asymptote is a value that a function may approach, but will never actually attain. In the case of vertical asymptotes, this behavior occurs if the function approaches infinity for a given x-value, often when a zero value appears in a denominator. Noting this rule, the above function has a zero in the denominator at a definite point centered approximately around:

We find a zero denominator for the function:

Example Question #16 : Connect Infinite Limits And Vertical/Horizontal Asymptotes

Screen shot 2020 09 04 at 9.53.48 am

Of the following functions, which most likely represent the same data above?

Possible Answers:

Correct answer:

Explanation:

Observation of the data points shows that there is a sharp increase and decrease on either side of a particular x-value. This type of behavior is observed when there is a vertical asymptote. An asymptote is a value that a function may approach, but will never actually attain. In the case of vertical asymptotes, this behavior occurs if the function approaches infinity for a given x-value, often when a zero value appears in a denominator. Noting this rule, the above function has a zero in the denominator at a definite point centered approximately around:

We find a zero denominator for the function:

Example Question #17 : Connect Infinite Limits And Vertical/Horizontal Asymptotes

Screen shot 2020 09 04 at 9.48.40 am

Of the following functions, which most likely represent the same data above?

Possible Answers:

Correct answer:

Explanation:

Notice that as x increases, the points of data graphed appears to level out, flattening towards a certain value. This value is what is known as a horizontal asymptote. An asymptote is a value that a function approaches, but never actually reaches. Think of a horizontal asymptote as a limit of a function as x approaches infinity. In such a case, as x approaches infinity, any constants added or subtracted in the numerator and denominator become irrelevant. What matters is the power of x in the denominator and the numerator; if those are the same, then to coefficients define the asymptote. We see that the function flattens towards:

This matches the ratio of coefficients for the function:

Example Question #18 : Connect Infinite Limits And Vertical/Horizontal Asymptotes

Screen shot 2020 09 04 at 9.51.29 am

Decide which of the following functions, most likely represents the same data above.

Possible Answers:

Correct answer:

Explanation:

Notice that as x increases, the points of data graphed appears to level out, flattening towards a certain value. This value is what is known as a horizontal asymptote. An asymptote is a value that a function approaches, but never actually reaches. Think of a horizontal asymptote as a limit of a function as x approaches infinity. In such a case, as x approaches infinity, any constants added or subtracted in the numerator and denominator become irrelevant. What matters is the power of x in the denominator and the numerator; if those are the same, then to coefficients define the asymptote. We see that the function flattens towards: 

This matches the ratio of coefficients for the function:

Example Question #19 : Connect Infinite Limits And Vertical/Horizontal Asymptotes

Screen shot 2020 09 04 at 9.55.57 am

Decide which of the following functions, most likely represents the sample data above.

Possible Answers:

Correct answer:

Explanation:

Notice that as x increases, the points of data graphed appears to level out, flattening towards a certain value. This value is what is known as a horizontal asymptote. An asymptote is a value that a function approaches, but never actually reaches. Think of a horizontal asymptote as a limit of a function as x approaches infinity. In such a case, as x approaches infinity, any constants added or subtracted in the numerator and denominator become irrelevant. What matters is the power of x in the denominator and the numerator; if those are the same, then to coefficients define the asymptote. We see that the function flattens towards:

This matches the ratio of coefficients for the function:

Example Question #20 : Connect Infinite Limits And Vertical/Horizontal Asymptotes

Screen shot 2020 09 04 at 9.58.50 am

Which of the four following functions is most likely depicted in the sample data above?

Possible Answers:

Correct answer:

Explanation:

Observation of the data points shows that there is a sharp increase and decrease on either side of a particular x-value. This type of behavior is observed when there is a vertical asymptote. An asymptote is a value that a function may approach, but will never actually attain. In the case of vertical asymptotes, this behavior occurs if the function approaches infinity for a given x-value, often when a zero value appears in a denominator. Noting this rule, the above function has a zero in the denominator at a definite point centered approximately around:

We find a zero denominator for the function:

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