<< Chapter < Page Chapter >> Page >

Consider the function f ( x ) = 5 x 2 / 3 . Determine the point on the graph where a cusp is located. Determine the end behavior of f .

The function f has a cusp at ( 0 , 5 ) lim x 0 f ( x ) = , lim x 0 + f ( x ) = . For end behavior, lim x ± f ( x ) = .

Got questions? Get instant answers now!

Key concepts

  • The limit of f ( x ) is L as x (or as x ) if the values f ( x ) become arbitrarily close to L as x becomes sufficiently large.
  • The limit of f ( x ) is as x if f ( x ) becomes arbitrarily large as x becomes sufficiently large. The limit of f ( x ) is as x if f ( x ) < 0 and | f ( x ) | becomes arbitrarily large as x becomes sufficiently large. We can define the limit of f ( x ) as x approaches similarly.
  • For a polynomial function p ( x ) = a n x n + a n 1 x n 1 + + a 1 x + a 0 , where a n 0 , the end behavior is determined by the leading term a n x n . If n 0 , p ( x ) approaches or at each end.
  • For a rational function f ( x ) = p ( x ) q ( x ) , the end behavior is determined by the relationship between the degree of p and the degree of q . If the degree of p is less than the degree of q , the line y = 0 is a horizontal asymptote for f . If the degree of p is equal to the degree of q , then the line y = a n b n is a horizontal asymptote, where a n and b n are the leading coefficients of p and q , respectively. If the degree of p is greater than the degree of q , then f approaches or at each end.

For the following exercises, examine the graphs. Identify where the vertical asymptotes are located.

For the following functions f ( x ) , determine whether there is an asymptote at x = a . Justify your answer without graphing on a calculator.

f ( x ) = x + 1 x 2 + 5 x + 4 , a = −1

Got questions? Get instant answers now!

f ( x ) = x x 2 , a = 2

Yes, there is a vertical asymptote

Got questions? Get instant answers now!

f ( x ) = ( x + 2 ) 3 / 2 , a = −2

Got questions? Get instant answers now!

f ( x ) = ( x 1 ) −1 / 3 , a = 1

Yes, there is vertical asymptote

Got questions? Get instant answers now!

f ( x ) = 1 + x −2 / 5 , a = 1

Got questions? Get instant answers now!

For the following exercises, evaluate the limit.

lim x 1 3 x + 6

0

Got questions? Get instant answers now!

lim x 2 x 5 4 x

Got questions? Get instant answers now!

lim x x 2 2 x + 5 x + 2

Got questions? Get instant answers now!

lim x 3 x 3 2 x x 2 + 2 x + 8

Got questions? Get instant answers now!

lim x x 4 4 x 3 + 1 2 2 x 2 7 x 4

1 7

Got questions? Get instant answers now!

lim x 3 x x 2 + 1

Got questions? Get instant answers now!

lim x 4 x 2 1 x + 2

−2

Got questions? Get instant answers now!

lim x 4 x x 2 1

Got questions? Get instant answers now!

lim x 4 x x 2 1

−4

Got questions? Get instant answers now!

lim x 2 x x x + 1

Got questions? Get instant answers now!

For the following exercises, find the horizontal and vertical asymptotes.

f ( x ) = x 9 x

Horizontal: none, vertical: x = 0

Got questions? Get instant answers now!

f ( x ) = x 3 4 x 2

Horizontal: none, vertical: x = ± 2

Got questions? Get instant answers now!

f ( x ) = x 2 + 3 x 2 + 1

Got questions? Get instant answers now!

f ( x ) = sin ( x ) sin ( 2 x )

Horizontal: none, vertical: none

Got questions? Get instant answers now!

f ( x ) = cos x + cos ( 3 x ) + cos ( 5 x )

Got questions? Get instant answers now!

f ( x ) = x sin ( x ) x 2 1

Horizontal: y = 0 , vertical: x = ± 1

Got questions? Get instant answers now!

f ( x ) = 1 x 3 + x 2

Horizontal: y = 0 , vertical: x = 0 and x = −1

Got questions? Get instant answers now!

f ( x ) = 1 x 1 2 x

Got questions? Get instant answers now!

f ( x ) = x 3 + 1 x 3 1

Horizontal: y = 1 , vertical: x = 1

Got questions? Get instant answers now!

f ( x ) = sin x + cos x sin x cos x

Got questions? Get instant answers now!

f ( x ) = x sin x

Horizontal: none, vertical: none

Got questions? Get instant answers now!

For the following exercises, construct a function f ( x ) that has the given asymptotes.

x = 1 and y = 2

Answers will vary, for example: y = 2 x x 1

Got questions? Get instant answers now!

y = 4 , x = −1

Answers will vary, for example: y = 4 x x + 1

Got questions? Get instant answers now!

For the following exercises, graph the function on a graphing calculator on the window x = [ −5 , 5 ] and estimate the horizontal asymptote or limit. Then, calculate the actual horizontal asymptote or limit.

[T] f ( x ) = 1 x + 10

y = 0

Got questions? Get instant answers now!

[T] f ( x ) = x + 1 x 2 + 7 x + 6

Got questions? Get instant answers now!

[T] lim x x 2 + 10 x + 25

Got questions? Get instant answers now!

[T] lim x x + 2 x 2 + 7 x + 6

Got questions? Get instant answers now!

[T] lim x 3 x + 2 x + 5

y = 3

Got questions? Get instant answers now!

For the following exercises, draw a graph of the functions without using a calculator. Be sure to notice all important features of the graph: local maxima and minima, inflection points, and asymptotic behavior.

y = 2 x + 1 x 2 + 6 x + 5

Got questions? Get instant answers now!

y = x 3 + 4 x 2 + 3 x 3 x + 9


An upward-facing parabola with minimum between x = 0 and x = −1 with y intercept between 0 and 1.

Got questions? Get instant answers now!

y = x 2 + x 2 x 2 3 x 4

Got questions? Get instant answers now!

y = cos x x , on x = [ −2 π , 2 π ]


This graph has vertical asymptote at x = 0. The first part of the function occurs in the second and third quadrants and starts in the third quadrant just below (−2π, 0), increases and passes through the x axis at −3π/2, reaches a maximum and then decreases through the x axis at −π/2 before approaching the asymptote. On the other side of the asymptote, the function starts in the first quadrant, decreases quickly to pass through π/2, decreases to a local minimum and then increases through (3π/2, 0) before staying just above (2π, 0).

Got questions? Get instant answers now!

y = x tan x , x = [ π , π ]


This graph has vertical asymptotes at x = ±π/2. The graph is symmetric about the y axis, so describing the left hand side will be sufficient. The function starts at (−π, 0) and decreases quickly to the asymptote. Then it starts on the other side of the asymptote in the second quadrant and decreases to the the origin.

Got questions? Get instant answers now!

y = x 2 sin ( x ) , x = [ −2 π , 2 π ]


This function starts at (−2π, 0), increases to near (−3π/2, 25), decreases through (−π, 0), achieves a local minimum and then increases through the origin. On the other side of the origin, the graph is the same but flipped, that is, it is congruent to the other half by a rotation of 180 degrees.

Got questions? Get instant answers now!

For f ( x ) = P ( x ) Q ( x ) to have an asymptote at y = 2 then the polynomials P ( x ) and Q ( x ) must have what relation?

Got questions? Get instant answers now!

For f ( x ) = P ( x ) Q ( x ) to have an asymptote at x = 0 , then the polynomials P ( x ) and Q ( x ) . must have what relation?

Q ( x ) . must have have x k + 1 as a factor, where P ( x ) has x k as a factor.

Got questions? Get instant answers now!

If f ( x ) has asymptotes at y = 3 and x = 1 , then f ( x ) has what asymptotes?

Got questions? Get instant answers now!

Both f ( x ) = 1 ( x 1 ) and g ( x ) = 1 ( x 1 ) 2 have asymptotes at x = 1 and y = 0 . What is the most obvious difference between these two functions?

lim x 1 f ( x ) and lim x 1 g ( x )

Got questions? Get instant answers now!

True or false: Every ratio of polynomials has vertical asymptotes.

Got questions? Get instant answers now!

Questions & Answers

what is biology
Hajah Reply
the study of living organisms and their interactions with one another and their environments
AI-Robot
what is biology
Victoria Reply
HOW CAN MAN ORGAN FUNCTION
Alfred Reply
the diagram of the digestive system
Assiatu Reply
allimentary cannel
Ogenrwot
How does twins formed
William Reply
They formed in two ways first when one sperm and one egg are splited by mitosis or two sperm and two eggs join together
Oluwatobi
what is genetics
Josephine Reply
Genetics is the study of heredity
Misack
how does twins formed?
Misack
What is manual
Hassan Reply
discuss biological phenomenon and provide pieces of evidence to show that it was responsible for the formation of eukaryotic organelles
Joseph Reply
what is biology
Yousuf Reply
the study of living organisms and their interactions with one another and their environment.
Wine
discuss the biological phenomenon and provide pieces of evidence to show that it was responsible for the formation of eukaryotic organelles in an essay form
Joseph Reply
what is the blood cells
Shaker Reply
list any five characteristics of the blood cells
Shaker
lack electricity and its more savely than electronic microscope because its naturally by using of light
Abdullahi Reply
advantage of electronic microscope is easily and clearly while disadvantage is dangerous because its electronic. advantage of light microscope is savely and naturally by sun while disadvantage is not easily,means its not sharp and not clear
Abdullahi
cell theory state that every organisms composed of one or more cell,cell is the basic unit of life
Abdullahi
is like gone fail us
DENG
cells is the basic structure and functions of all living things
Ramadan
What is classification
ISCONT Reply
is organisms that are similar into groups called tara
Yamosa
in what situation (s) would be the use of a scanning electron microscope be ideal and why?
Kenna Reply
A scanning electron microscope (SEM) is ideal for situations requiring high-resolution imaging of surfaces. It is commonly used in materials science, biology, and geology to examine the topography and composition of samples at a nanoscale level. SEM is particularly useful for studying fine details,
Hilary
cell is the building block of life.
Condoleezza Reply
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply
Practice Key Terms 5

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Calculus volume 1. OpenStax CNX. Feb 05, 2016 Download for free at http://cnx.org/content/col11964/1.2
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Calculus volume 1' conversation and receive update notifications?

Ask