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For the following exercises, use function composition to verify that f ( x ) and g ( x ) are inverse functions.

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

  f ( g ( x ) ) = x , g ( f ( x ) ) = x

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f ( x ) = 3 x + 5 and g ( x ) = x 5 3

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Graphical

For the following exercises, use a graphing utility to determine whether each function is one-to-one.

f ( x ) = −5 x + 1

one-to-one

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For the following exercises, determine whether the graph represents a one-to-one function.

For the following exercises, use the graph of f shown in [link] .

Graph of a line.

Find f 1 ( 0 ) .

2

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Solve f 1 ( x ) = 0.

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For the following exercises, use the graph of the one-to-one function shown in [link] .

Graph of a square root function.

Sketch the graph of f 1 .

Graph of a square root function and its inverse.
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Find f ( 6 )  and  f 1 ( 2 ) .

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If the complete graph of f is shown, find the domain of f .

[ 2 , 10 ]

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If the complete graph of f is shown, find the range of f .

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Numeric

For the following exercises, evaluate or solve, assuming that the function f is one-to-one.

If f ( 6 ) = 7 , find f 1 ( 7 ) .

6

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If f ( 3 ) = 2 , find f 1 ( 2 ) .

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If f 1 ( 4 ) = 8 , find f ( 8 ) .

4

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If f 1 ( 2 ) = 1 , find f ( 1 ) .

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For the following exercises, use the values listed in [link] to evaluate or solve.

x f ( x )
0 8
1 0
2 7
3 4
4 2
5 6
6 5
7 3
8 9
9 1

Find f 1 ( 0 ) .

1

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Solve f 1 ( x ) = 7.

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Use the tabular representation of f in [link] to create a table for f 1 ( x ) .

x 3 6 9 13 14
f ( x ) 1 4 7 12 16
x 1 4 7 12 16
f 1 ( x ) 3 6 9 13 14
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Technology

For the following exercises, find the inverse function. Then, graph the function and its inverse.

f ( x ) = x 3 1

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

Graph of a cubic function and its inverse.
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Find the inverse function of f ( x ) = 1 x 1 . Use a graphing utility to find its domain and range. Write the domain and range in interval notation.

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Real-world applications

To convert from x degrees Celsius to y degrees Fahrenheit, we use the formula f ( x ) = 9 5 x + 32. Find the inverse function, if it exists, and explain its meaning.

f 1 ( x ) = 5 9 ( x 32 ) . Given the Fahrenheit temperature, x , this formula allows you to calculate the Celsius temperature.

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The circumference C of a circle is a function of its radius given by C ( r ) = 2 π r . Express the radius of a circle as a function of its circumference. Call this function r ( C ) . Find r ( 36 π ) and interpret its meaning.

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A car travels at a constant speed of 50 miles per hour. The distance the car travels in miles is a function of time, t , in hours given by d ( t ) = 50 t . Find the inverse function by expressing the time of travel in terms of the distance traveled. Call this function t ( d ) . Find t ( 180 ) and interpret its meaning.

t ( d ) = d 50 , t ( 180 ) = 180 50 . The time for the car to travel 180 miles is 3.6 hours.

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Chapter review exercises

Functions and Function Notation

For the following exercises, determine whether the relation is a function.

{ ( a , b ) , ( c , d ) , ( e , d ) }

function

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{ ( 5 , 2 ) , ( 6 , 1 ) , ( 6 , 2 ) , ( 4 , 8 ) }

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y 2 + 4 = x , for x the independent variable and y the dependent variable

not a function

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Is the graph in [link] a function?

Graph of a parabola.
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For the following exercises, evaluate the function at the indicated values: f ( 3 ) ; f ( 2 ) ; f ( a ) ; f ( a ) ; f ( a + h ) .

f ( x ) = 2 x 2 + 3 x

f ( 3 ) = 27 ; f ( 2 ) = 2 ; f ( a ) = 2 a 2 3 a ;
f ( a ) = 2 a 2 3 a ; f ( a + h ) = 2 a 2 + 3 a 4 a h + 3 h 2 h 2

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f ( x ) = 2 | 3 x 1 |

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For the following exercises, determine whether the functions are one-to-one.

Questions & Answers

for the "hiking" mix, there are 1,000 pieces in the mix, containing 390.8 g of fat, and 165 g of protein. if there is the same amount of almonds as cashews, how many of each item is in the trail mix?
ADNAN Reply
linear speed of an object
Melissa Reply
an object is traveling around a circle with a radius of 13 meters .if in 20 seconds a central angle of 1/7 Radian is swept out what are the linear and angular speed of the object
Melissa
test
Matrix
how to find domain
Mohamed Reply
like this: (2)/(2-x) the aim is to see what will not be compatible with this rational expression. If x= 0 then the fraction is undefined since we cannot divide by zero. Therefore, the domain consist of all real numbers except 2.
Dan
define the term of domain
Moha
if a>0 then the graph is concave
Angel Reply
if a<0 then the graph is concave blank
Angel
what's a domain
Kamogelo Reply
The set of all values you can use as input into a function su h that the output each time will be defined, meaningful and real.
Spiro
how fast can i understand functions without much difficulty
Joe Reply
what is inequalities
Nathaniel
functions can be understood without a lot of difficulty. Observe the following: f(2) 2x - x 2(2)-2= 2 now observe this: (2,f(2)) ( 2, -2) 2(-x)+2 = -2 -4+2=-2
Dan
what is set?
Kelvin Reply
a colony of bacteria is growing exponentially doubling in size every 100 minutes. how much minutes will it take for the colony of bacteria to triple in size
Divya Reply
I got 300 minutes. is it right?
Patience
no. should be about 150 minutes.
Jason
It should be 158.5 minutes.
Mr
ok, thanks
Patience
100•3=300 300=50•2^x 6=2^x x=log_2(6) =2.5849625 so, 300=50•2^2.5849625 and, so, the # of bacteria will double every (100•2.5849625) = 258.49625 minutes
Thomas
158.5 This number can be developed by using algebra and logarithms. Begin by moving log(2) to the right hand side of the equation like this: t/100 log(2)= log(3) step 1: divide each side by log(2) t/100=1.58496250072 step 2: multiply each side by 100 to isolate t. t=158.49
Dan
what is the importance knowing the graph of circular functions?
Arabella Reply
can get some help basic precalculus
ismail Reply
What do you need help with?
Andrew
how to convert general to standard form with not perfect trinomial
Camalia Reply
can get some help inverse function
ismail
Rectangle coordinate
Asma Reply
how to find for x
Jhon Reply
it depends on the equation
Robert
yeah, it does. why do we attempt to gain all of them one side or the other?
Melissa
how to find x: 12x = 144 notice how 12 is being multiplied by x. Therefore division is needed to isolate x and whatever we do to one side of the equation we must do to the other. That develops this: x= 144/12 divide 144 by 12 to get x. addition: 12+x= 14 subtract 12 by each side. x =2
Dan
whats a domain
mike Reply
The domain of a function is the set of all input on which the function is defined. For example all real numbers are the Domain of any Polynomial function.
Spiro
Spiro; thanks for putting it out there like that, 😁
Melissa
foci (–7,–17) and (–7,17), the absolute value of the differenceof the distances of any point from the foci is 24.
Churlene Reply
Practice Key Terms 1

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Source:  OpenStax, Precalculus. OpenStax CNX. Jan 19, 2016 Download for free at https://legacy.cnx.org/content/col11667/1.6
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