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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.

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

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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 , ) .

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

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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.

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Algebraic

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

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

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f ( x ) = 5 2 x 2

( , )

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f ( x ) = 3 6 2 x

( , 3 ]

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f ( x ) = x 2 + 4

( , )

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f ( x ) = x 1 3

( , )

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

( , 1 2 ) ( 1 2 , )

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

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

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f ( x ) = 1 x 2 x 6

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

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

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2 x + 1 5 x

( , 5 )

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f ( x ) = x 4 x 6

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f ( x ) = x 6 x 4

[ 6 , )

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

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

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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.
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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 )

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Graph of a function from [-4, 4].

domain: [ 4 ,  4], range: [ 0 ,  2]

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Graph of a function from [-5, 3).

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

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Graph of a function from (-infinity, 2].

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

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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 ]

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Graph of a function from [-3, infinity).

domain: [ 3 ,   ) ; range: [ 0 , )

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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

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

domain: ( , )

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

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

domain: ( , )

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

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

domain: ( , )

Graph of f(x).
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f ( x ) = { x + 1 if x < 1 x 3 if x 1

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

domain: ( , )

Graph of f(x).
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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

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f ( x ) = { 1 if  x 3 0 if  x > 3

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

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

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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

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

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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

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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

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

domain: ( , 1 ) ( 1 , )

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

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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 ]

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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.

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Extension

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

[ 0 ,   8 ]

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

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

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

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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

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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 ) ?
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Questions & Answers

how does Neisseria cause meningitis
Nyibol Reply
what is microbiologist
Muhammad Reply
what is errata
Muhammad
is the branch of biology that deals with the study of microorganisms.
Ntefuni Reply
What is microbiology
Mercy Reply
studies of microbes
Louisiaste
when we takee the specimen which lumbar,spin,
Ziyad Reply
How bacteria create energy to survive?
Muhamad Reply
Bacteria doesn't produce energy they are dependent upon their substrate in case of lack of nutrients they are able to make spores which helps them to sustain in harsh environments
_Adnan
But not all bacteria make spores, l mean Eukaryotic cells have Mitochondria which acts as powerhouse for them, since bacteria don't have it, what is the substitution for it?
Muhamad
they make spores
Louisiaste
what is sporadic nd endemic, epidemic
Aminu Reply
the significance of food webs for disease transmission
Abreham
food webs brings about an infection as an individual depends on number of diseased foods or carriers dully.
Mark
explain assimilatory nitrate reduction
Esinniobiwa Reply
Assimilatory nitrate reduction is a process that occurs in some microorganisms, such as bacteria and archaea, in which nitrate (NO3-) is reduced to nitrite (NO2-), and then further reduced to ammonia (NH3).
Elkana
This process is called assimilatory nitrate reduction because the nitrogen that is produced is incorporated in the cells of microorganisms where it can be used in the synthesis of amino acids and other nitrogen products
Elkana
Examples of thermophilic organisms
Shu Reply
Give Examples of thermophilic organisms
Shu
advantages of normal Flora to the host
Micheal Reply
Prevent foreign microbes to the host
Abubakar
they provide healthier benefits to their hosts
ayesha
They are friends to host only when Host immune system is strong and become enemies when the host immune system is weakened . very bad relationship!
Mark
what is cell
faisal Reply
cell is the smallest unit of life
Fauziya
cell is the smallest unit of life
Akanni
ok
Innocent
cell is the structural and functional unit of life
Hasan
is the fundamental units of Life
Musa
what are emergency diseases
Micheal Reply
There are nothing like emergency disease but there are some common medical emergency which can occur simultaneously like Bleeding,heart attack,Breathing difficulties,severe pain heart stock.Hope you will get my point .Have a nice day ❣️
_Adnan
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Innocent
I think infection prevention and control is the avoidance of all things we do that gives out break of infections and promotion of health practices that promote life
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ESTHER Reply
Many sites of the body have it Skin Nasal cavity Oral cavity Gastro intestinal tract
Safaa
skin
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part of a tissue or an organ being wounded or bruised.
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Binomial nomenclature
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Source:  OpenStax, College algebra. OpenStax CNX. Feb 06, 2015 Download for free at https://legacy.cnx.org/content/col11759/1.3
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