<< Chapter < Page Chapter >> Page >

Section exercises

Verbal

Why does the domain differ for different functions?

The domain of a function depends upon what values of the independent variable make the function undefined or imaginary.

Got questions? Get instant answers now!

How do we determine the domain of a function defined by an equation?

Got questions? Get instant answers now!

Explain why the domain of f ( x ) = x 3 is different from the domain of f ( x ) = x .

There is no restriction on x for f ( x ) = x 3 because you can take the cube root of any real number. So the domain is all real numbers, ( , ) . When dealing with the set of real numbers, you cannot take the square root of negative numbers. So x -values are restricted for f ( x ) = x to nonnegative numbers and the domain is [ 0 , ) .

Got questions? Get instant answers now!

When describing sets of numbers using interval notation, when do you use a parenthesis and when do you use a bracket?

Got questions? Get instant answers now!

How do you graph a piecewise function?

Graph each formula of the piecewise function over its corresponding domain. Use the same scale for the x -axis and y -axis for each graph. Indicate inclusive endpoints with a solid circle and exclusive endpoints with an open circle. Use an arrow to indicate or   . Combine the graphs to find the graph of the piecewise function.

Got questions? Get instant answers now!

Algebraic

For the following exercises, find the domain of each function using interval notation.

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

Got questions? Get instant answers now!

f ( x ) = 5 2 x 2

( , )

Got questions? Get instant answers now!

f ( x ) = 3 6 2 x

( , 3 ]

Got questions? Get instant answers now!

f ( x ) = x 2 + 4

( , )

Got questions? Get instant answers now!

f ( x ) = x 1 3

( , )

Got questions? Get instant answers now!

f ( x ) = 3 x + 1 4 x + 2

( , 1 2 ) ( 1 2 , )

Got questions? Get instant answers now!

f ( x ) = x 3 x 2 + 9 x 22

( , 11 ) ( 11 , 2 ) ( 2 , )

Got questions? Get instant answers now!

f ( x ) = 1 x 2 x 6

Got questions? Get instant answers now!

f ( x ) = 2 x 3 250 x 2 2 x 15

( , 3 ) ( 3 , 5 ) ( 5 , )

Got questions? Get instant answers now!

2 x + 1 5 x

( , 5 )

Got questions? Get instant answers now!

f ( x ) = x 4 x 6

Got questions? Get instant answers now!

f ( x ) = x 6 x 4

[ 6 , )

Got questions? Get instant answers now!

f ( x ) = x 2 9 x x 2 81

( , 9 ) ( 9 , 9 ) ( 9 , )

Got questions? Get instant answers now!

Find the domain of the function f ( x ) = 2 x 3 50 x by:

  1. using algebra.
  2. graphing the function in the radicand and determining intervals on the x -axis for which the radicand is nonnegative.
Got questions? Get instant answers now!

Graphical

For the following exercises, write the domain and range of each function using interval notation.

Graph of a function from (2, 8].

domain: ( 2 , 8 ] , range [ 6 , 8 )

Got questions? Get instant answers now!
Graph of a function from [-4, 4].

domain: [ 4 ,  4], range: [ 0 ,  2]

Got questions? Get instant answers now!
Graph of a function from [-5, 3).

domain: [ 5 ,   3 ) , range: [ 0 , 2 ]

Got questions? Get instant answers now!
Graph of a function from (-infinity, 2].

domain: ( , 1 ] , range: [ 0 , )

Got questions? Get instant answers now!
Graph of a function from [-6, -1/6]U[1/6, 6]/.

domain: [ 6 , 1 6 ] [ 1 6 , 6 ] ; range: [ 6 , 1 6 ] [ 1 6 , 6 ]

Got questions? Get instant answers now!
Graph of a function from [-3, infinity).

domain: [ 3 ,   ) ; range: [ 0 , )

Got questions? Get instant answers now!

For the following exercises, sketch a graph of the piecewise function. Write the domain in interval notation.

f ( x ) = { x + 1 if x < 2 2 x 3 if x 2

Got questions? Get instant answers now!

f ( x ) = { 2 x 1 if x < 1 1 + x if x 1

domain: ( , )

Graph of f(x).
Got questions? Get instant answers now!

f ( x ) = { x + 1 if x < 0 x 1 if x > 0

Got questions? Get instant answers now!

f ( x ) = { 3 if x < 0 x if x 0

domain: ( , )

Graph of f(x).
Got questions? Get instant answers now!

f ( x ) = { x 2       if  x < 0 1 x   if  x > 0

Got questions? Get instant answers now!

f ( x ) = { x 2 x + 2 if x < 0 if x 0

domain: ( , )

Graph of f(x).
Got questions? Get instant answers now!

f ( x ) = { x + 1 if x < 1 x 3 if x 1

Got questions? Get instant answers now!

f ( x ) = { | x | 1 if x < 2 if x 2

domain: ( , )

Graph of f(x).
Got questions? Get instant answers now!

Numeric

For the following exercises, given each function f , evaluate f ( −3 ) , f ( −2 ) , f ( −1 ) , and f ( 0 ) .

f ( x ) = { x + 1 if x < 2 2 x 3 if x 2

Got questions? Get instant answers now!

f ( x ) = { 1 if  x 3 0 if  x > 3

f ( 3 ) = 1 ; f ( 2 ) = 0 ; f ( 1 ) = 0 ; f ( 0 ) = 0

Got questions? Get instant answers now!

f ( x ) = { 2 x 2 + 3 if  x 1 5 x 7 if  x > 1

Got questions? Get instant answers now!

For the following exercises, given each function f , evaluate f ( −1 ) , f ( 0 ) , f ( 2 ) , and f ( 4 ) .

f ( x ) = { 7 x + 3 if x < 0 7 x + 6 if x 0

f ( 1 ) = 4 ; f ( 0 ) = 6 ; f ( 2 ) = 20 ; f ( 4 ) = 34

Got questions? Get instant answers now!

f ( x ) = { x 2 2 if x < 2 4 + | x 5 | if x 2

Got questions? Get instant answers now!

f ( x ) = { 5 x if x < 0 3 if 0 x 3 x 2 if x > 3

f ( 1 ) = 5 ; f ( 0 ) = 3 ; f ( 2 ) = 3 ; f ( 4 ) = 16

Got questions? Get instant answers now!

For the following exercises, write the domain for the piecewise function in interval notation.

f ( x ) = { x + 1  if x < 2 2 x 3 if x 2

Got questions? Get instant answers now!

f ( x ) = { x 2 2  if x < 1 x 2 + 2 if x > 1

domain: ( , 1 ) ( 1 , )

Got questions? Get instant answers now!

f ( x ) = { 2 x 3 3 x 2 if x < 0 if x 2

Got questions? Get instant answers now!

Technology

Graph y = 1 x 2 on the viewing window [ −0.5 , −0.1 ] and [ 0.1 , 0.5 ] . Determine the corresponding range for the viewing window. Show the graphs.

Graph of the equation from [-0.5, -0.1].

window: [ 0.5 , 0.1 ] ; range: [ 4 ,   100 ]

Graph of the equation from [0.1, 0.5].

window: [ 0.1 ,   0.5 ] ; range: [ 4 ,   100 ]

Got questions? Get instant answers now!

Graph y = 1 x on the viewing window [ −0.5 , −0.1 ] and [ 0.1 ,   0.5 ] . Determine the corresponding range for the viewing window. Show the graphs.

Got questions? Get instant answers now!

Extension

Suppose the range of a function f is [ −5 ,   8 ] . What is the range of | f ( x ) | ?

[ 0 ,   8 ]

Got questions? Get instant answers now!

Create a function in which the range is all nonnegative real numbers.

Got questions? Get instant answers now!

Create a function in which the domain is x > 2.

Many answers. One function is f ( x ) = 1 x 2 .

Got questions? Get instant answers now!

Real-world applications

The height h of a projectile is a function of the time t it is in the air. The height in feet for t seconds is given by the function h ( t ) = −16 t 2 + 96 t . What is the domain of the function? What does the domain mean in the context of the problem?

The domain is [ 0 ,   6 ] ; it takes 6 seconds for the projectile to leave the ground and return to the ground

Got questions? Get instant answers now!

The cost in dollars of making x items is given by the function C ( x ) = 10 x + 500.

  1. The fixed cost is determined when zero items are produced. Find the fixed cost for this item.
  2. What is the cost of making 25 items?
  3. Suppose the maximum cost allowed is $1500. What are the domain and range of the cost function, C ( x ) ?
Got questions? Get instant answers now!

Questions & Answers

what's Thermochemistry
rhoda Reply
the study of the heat energy which is associated with chemical reactions
Kaddija
How was CH4 and o2 was able to produce (Co2)and (H2o
Edafe Reply
explain please
Victory
First twenty elements with their valences
Martine Reply
what is chemistry
asue Reply
what is atom
asue
what is the best way to define periodic table for jamb
Damilola Reply
what is the change of matter from one state to another
Elijah Reply
what is isolation of organic compounds
IKyernum Reply
what is atomic radius
ThankGod Reply
Read Chapter 6, section 5
Dr
Read Chapter 6, section 5
Kareem
Atomic radius is the radius of the atom and is also called the orbital radius
Kareem
atomic radius is the distance between the nucleus of an atom and its valence shell
Amos
Read Chapter 6, section 5
paulino
Bohr's model of the theory atom
Ayom Reply
is there a question?
Dr
when a gas is compressed why it becomes hot?
ATOMIC
It has no oxygen then
Goldyei
read the chapter on thermochemistry...the sections on "PV" work and the First Law of Thermodynamics should help..
Dr
Which element react with water
Mukthar Reply
Mgo
Ibeh
an increase in the pressure of a gas results in the decrease of its
Valentina Reply
definition of the periodic table
Cosmos Reply
What is the lkenes
Da Reply
what were atoms composed of?
Moses Reply
what is chemistry
Imoh Reply
what is chemistry
Damilola
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply
Practice Key Terms 3

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Precalculus. OpenStax CNX. Jan 19, 2016 Download for free at https://legacy.cnx.org/content/col11667/1.6
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Precalculus' conversation and receive update notifications?

Ask