Nelson Functions 11
Nelson Functions 11
1st Edition
Chris Kirkpatrick, Marian Small
ISBN: 9780176332037
Textbook solutions

All Solutions

Section 1-5: The Inverse Function and Its Properties

Exercise 1
Step 1
1 of 3
a) Relation is $left{(-2,3), (0,4), (2,5), (4,6) right}$

If we switch the x- and y-coordinates
of each point in the graph, we get the inverse relation.

Inverse relation is $left{(3,-2), (4,0), (5,2), (6,4) right}$

see graph: the points on one side of the line were mirror images of the points on the other side. Now can conclude: this relation is a functionExercise scan
Step 2
2 of 3
a) Relation is $left{(2,5), (2,-1), (3,1), (5,1) right}$

If we switch the x- and y-coordinates
of each point in the graph, we get the inverse relation.

Inverse relation is $left{(5,2), (-1,2), (1,3), (1,5) right}$

see graph: the points on one side of the line were mirror images of the points on the other side. Now can conclude: this relation is a functionExercise scan
Result
3 of 3
a) ${ (3,-2),; (4,0),; (5,2),; (6,4) }$

Both are functions.

b) ${(5,2),;(-1,2),;(1,3),;(1,5)}$

Both are NOT functions.

Graphs have been plotted in the answers.

Exercise 2
Step 1
1 of 7
a) Relation is

$left{(-2,-5), (-1,-3), (0,-1), (1,1), (2,3), (3,5) right}$
(these points is blue on the graph)

If we switch the x- and y-coordinates
of each point in the graph, we get the inverse relation.

Inverse relation is

$left{(-5,-2), (-3,-1), (-1,0), (1,1), (3,2), (5,3)right}$

(these points is red on the graph )

This relation is a function because each element of the domain has only one corresponding element in the range. Common point is $(1,1)$

see graph:the points on one side of the line were mirror images of the points on the other side.Exercise scan
Step 2
2 of 7
a) Relation is

$left{(-5,-2), (-4,-2), (-3,-2), (-2,-2), (-1,-2), (0,-2), (1,-2), (2,-2), (3,-2), (4,-2), (5,-2) right}$

(these points is blue on the graph)

If we switch the x- and y-coordinates
of each point in the graph, we get the inverse relation.

Inverse relation is

$left{(-2,-5), (-2,-4), (-2,-3), (-2,-2), (-2,-1), (-2,0), (-2,1), (-2,2), (-2,3), (-2,4), (-2,5)right}$

(these points is red on the graph )

Inverse relation is not a function because Each element -2 of the domain has the different corresponding elements in the range, so the relation is not a function. Common point is $(-2,-2)$

see graph:the points on one side of the line were mirror images of the points on the other side.Exercise scan
Step 3
3 of 7
c) Use graph we can conclude relation is $y=1-3x$. This relation is a function because for each $xin R$ we get only one value of $y$. Or, we can see this relation passes vertical-line test. Any vertical line drawn on the graph intersects the graph at only one point. So, this is the graph of a function.

Now, we need determine inverse function:

$y=1-3x$ subtract 1 from both sides

$y-1=-3x$ multiply both side by -1

$-1(y-1)=-3x(-1)$

$1-y=3x$ divide both side by 3

$x=dfrac{1-y}{3}$

That means $f^{-1}(x)=dfrac{1-x}{3}$ or $f^{-1}(x)=dfrac{-1}{3}x+dfrac{1}{3}$ is inverse function.

The graph of $f^{-1}(x)=dfrac{1-x}{3}$ is a straight line with slope $-dfrac{1}{3}$. The graph passes the vertical-line test, so, the inverse relation is a function

Common point is A(0.25, 0.25)

Exercise scan
Step 4
4 of 7
d) Use graph we can conclude relation is $y=5x-5$. This relation is a function because for each $xin R$ we get only one value of $y$. Or, we can see this relation passes vertical-line test. Any vertical line drawn on the graph intersects the graph at only one point. So, this is the graph of a function.

Now, we need determine inverse function:

$y=5x-5$ add 5 to both sides

$y+5=5x$ divide both side by 5

$$
x=dfrac{y+5}{5}
$$

That means $f^{-1}(x)=dfrac{x+5}{5}$ or $f^{-1}(x)=dfrac{1}{5}x+dfrac{1}{5}$ is inverse function.

The graph of $f^{-1}(x)=dfrac{x+5}{5}$ is a straight line with slope $dfrac{1}{5}$. The graph passes the vertical-line test, so, the inverse relation is a function.

Common point is $a(1.25,1.25)$

Exercise scan
Step 5
5 of 7
e) Use graph we can conclude relation is $y=2x+2$. This relation is a function because for each $xin R$ we get only one value of $y$. Or, we can see this relation passes vertical-line test. Any vertical line drawn on the graph intersects the graph at only one point. So, this is the graph of a function.

Now, we need determine inverse function:

$y=2x+2$ subtract 2 from both sides

$y-2=2x$ divide both side by 2

$$
x=dfrac{y-2}{2}
$$

That means $f^{-1}(x)=dfrac{x-2}{2}$ or $f^{-1}(x)=dfrac{1}{2}x-1$ is inverse function.

The graph of $f^{-1}(x)=dfrac{x-2}{2}$ is a straight line with slope $dfrac{1}{2}$. The graph passes the vertical-line test, so, the inverse relation is a function.

Common point is $A(-2,-2)$

Exercise scan
Step 6
6 of 7
f) Use graph we can conclude relation is $y=2-x$. This relation is a function because for each $xin R$ we get only one value of $y$. Or, we can see this relation passes vertical-line test. Any vertical line drawn on the graph intersects the graph at only one point. So, this is the graph of a function.

Now, we need determine inverse function:

$y=2-x$ subtract 2 from both sides

$y-2=-x$ multiply both sides by -1

$x=2-y$
That means $f^{-1}(x)=2-x$ is inverse function.

The function $y=2-x$ and its inverse are the same. The graph passes the vertical-line test, so, the inverse relation is a function.

Exercise scan
Result
7 of 7
a) Function, point $(1,1)$ is common

b) NOT a function, point $(-2,-2)$ is common

c) Function, point $(0.25,0.25)$ is common

d) Function, point $(1.25, 1.25)$ is common

e) Function, point $(-2,-2)$ is common

f) Function. All points are common. The function and its inverse have the same graph.

Exercise 3
Step 1
1 of 3
a) Use algebraic notation we get

$f(x)=3x+1$ and $g(x)=dfrac{x}{3}-1$

Determine the inverse of linear function $f(x)=3x+1$:

$y=3x+1$ subtract 1 from both sides

$y-1=3x$ divide both side by 3

$x=dfrac{y-1}{3}$

The inverse function of $f(x)=3x+1$ is $f^{-1}(x)=dfrac{x-1}{3}$

Compare the inverse function with $g(x)$ we can conclude $f(x)$ and $g(x)$ ore not pair of inverse function.

Answer is: No

Step 2
2 of 3
b) a) Use algebraic notation we get

$f(x)=5x-2$ and $g(x)=dfrac{x+2}{5}$

Determine the inverse of linear function $f(x)=5x-2$:

$y=5x-2$ add 2 to both sides

$y+2=5x$ divide both side by 5

$x=dfrac{y+2}{5}$

The inverse function of $f(x)=5x-2$ is
$f^{-1}(x)=dfrac{x+2}{5}$

Compare the inverse function with $g(x)$ we can conclude $f(x)$ and $g(x)$ are pair of inverse function.

Answer is: Yes

Result
3 of 3
a) No

b) Yes

Exercise 4
Solution 1
Solution 2
Step 1
1 of 5
a) $y=4x-3$

Interchange $x$ and $y$

$x=4y-3$

Solve for $y$ in terms of $x$

$4y=x+3$

$$
y=dfrac{x+3}{4}
$$

Step 2
2 of 5
b) $y=2-dfrac{1}{2}x$

Interchange $x$ and $y$

$x=2-dfrac{1}{2}y$

Solve for $y$ in terms of $x$

$dfrac{1}{2}y=2-x$

$y=2(2-x)$

$$
y=4-2x
$$

Step 3
3 of 5
c) $3x+4y=6$

Interchange $x$ and $y$

$3y+4x=6$

Solve for $y$ in terms of $x$

$4y=6-4x$

$y=dfrac{6-4x}{3}$

$$
y=2-dfrac{4}{3}x
$$

Step 4
4 of 5
d) Interchange $x$ and $y$

$2x-10=5y$

Solve for $y$ in terms of $x$

$y=dfrac{2x-10}{5}$

$$
y=dfrac{2}{5}x-2
$$

Result
5 of 5
a) $y=dfrac{x+3}{4}$

b) $y=2(2-x)$

c) $y=2-dfrac{4}{3}x$

d) $y=dfrac{2}{5}x-2$

Step 1
1 of 5
$x=4y-3$

$x+3=4y$

$$
frac{x+3}{4}=y
$$

Part A
Step 2
2 of 5
$x=2-0.5y$

$x-2=0.5y$

$$
frac{x-2}{0.5}=y
$$

Part B
Step 3
3 of 5
$3y+4x=6$

$3y=6-4x$

$$
y=dfrac{6-4x}{3}
$$

Part C
Step 4
4 of 5
$2x-10=5y$

$$
dfrac{2x-10}{5}=y
$$

Part D
Result
5 of 5
See Solutions
Exercise 5
Step 1
1 of 7
a) $f(x)=x-4$ add 4 to both sides

$x=f(x)+4$

Inverse function is $f^{-1}(x)=x+4$

We used these inverse operations to write the equation of the inverse.

Step 2
2 of 7
b) $f(x)=3x+1$ subtract 1 from both sides

$f(x)-1=3x$ divide both side by 3

$x=dfrac{f(x)-1}{3}$

Inverse function is $f^{-1}(x)=dfrac{x-1}{3}$

Step 3
3 of 7
c) $f(x)=5x$ divide both side by 5

$x=dfrac{f(x)}{5}$

Inverse function is $f^{-1}(x)=dfrac{x}{5}$

Step 4
4 of 7
d) $f(x)=dfrac{1}{2}x -1$ add 1 to both sides

$f(x)+1=dfrac{1}{2}x$ multiply both side by 2

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

Inverse function is $f^{-1}(x)=2(x+1)$

Step 5
5 of 7
e) $f(x)=6-5x$ subtract 6 from both sides

$f(x)-6=-5x$ multiply both side by -1

$-1(f(x)-6)=-5x(-1)$

$6-f(x)=5x$ divide both side by 5

$x=dfrac{6-f(x)}{5}$

Inverse function is $f^{-1}(x)=dfrac{6-x}{5}$

Step 6
6 of 7
f) $f(x)=dfrac{3}{4}x+2$ subtract 2 to both sides

$f(x)-2=dfrac{3}{4}x$ multiply both side by 4

$4(f(x)-2)=3x$ divide both side by 3

$x=dfrac{4(f(x)-2)}{3}$

$x=dfrac{4}{3(f(x)-2)}$

Inverse function is $f^{-1}(x)=dfrac{4}{3}(x-2)$

Result
7 of 7
a) $f^{-1}(x)=x+4$

b) $f^{-1}(x)=dfrac{x-1}{3}$

c) $f^{-1}(x)=dfrac{1}{5}x$

d) $f^{-1}(x)=2(x+1)$

e) $f^{-1}(x)=dfrac{6-x}{5}$

f) $f^{-1}(x)=dfrac{4}{3}(x-2)$

Exercise 6
Step 1
1 of 7
a) Function is $f(x)=x+7$

Write the function in form $y=mx+b$ by putting $y$ in place of $f(x)$

$y=x+7$
switch $x$ and $y$ in the equation and solve for $y$

$x=y+7$ subtract 7 from both sides

$x-7=y$

Write the equation in function notation

$$
f^{-1}(x)=x-7
$$

Step 2
2 of 7
b) Function is $f(x)=2-x$

Write the function in form $y=mx+b$ by putting $y$ in place of $f(x)$

$y=2-x$
switch $x$ and $y$ in the equation and solve for $y$

$x=2-y$ subtract 2 from both sides

$x-2=-y$ multiply both side by -1

$$
2-x=y
$$

Write the equation in function notation

$$
f^{-1}(x)=2-x
$$

Step 3
3 of 7
c) a) Function is $f(x)=5$

Write the function in form $y=mx+b$ by putting $y$ in place of $f(x)$

$y=5$
switch $x$ and $y$ in the equation

$x=5$

Write the equation in function notation

$$
f^{-1}(x)=5
$$

Step 4
4 of 7
d) Function is $f(x)=-dfrac{1}{5}x-2$

Write the function in form $y=mx+b$ by putting $y$ in place of $f(x)$

$y=-dfrac{1}{5}x-2$
switch $x$ and $y$ in the equation and solve for $y$

$x=-dfrac{1}{5}y-2$ add 2 to both sides

$x+2=-dfrac{1}{5}y$ multiply both sides by -5

$-5(x+2)=y$ simplify

$-5x-10=y$

Write the equation in function notation

$$
f^{-1}(x)=-5x-10
$$

Step 5
5 of 7
e) Function is $f(x)=x$

Write the function in form $y=mx+b$ by putting $y$ in place of $f(x)$

$y=x$
switch $x$ and $y$ in the equation

$x=y$

Write the equation in function notation

$$
f^{-1}(x)=x
$$

Step 6
6 of 7
f) Function is $f(x)=dfrac{x-3}{4}$

Write the function in form $y=mx+b$ by putting $y$ in place of $f(x)$

$y=dfrac{x-3}{4}$
switch $x$ and $y$ in the equation and solve for $y$

$x=dfrac{y-3}{4}$ multiply both sides by 4

$4x=y-3$ add 3 to both sides

$$
4x+3=y
$$

Write the equation in function notation

$$
f^{-1}(x)=4x+3
$$

Result
7 of 7
a) $f^{1}(x)=x-7$

b) $f^{1}(x)=2-x$

c) $x=5$

d) $f^{1}(x)=-5(x+2)$

e) $f^{1}(x)=x$

f) $f^{-1}(x)=4x+3$

Exercise 7
Step 1
1 of 13
$bold{Concept:}$ The inverse of a linear function is always a linear function, except when the line has a slope of zero.

Question 5a)

The inverse is linear and a function because it passes the vertical line test.

Exercise scan

Step 2
2 of 13
Question 5b) The inverse is linear and a function since it passes the vertical line test.Exercise scan
Step 3
3 of 13
Question 5c) The inverse is both linear and a function.Exercise scan
Step 4
4 of 13
Question 5d) The inverse is both linear and a function.Exercise scan
Step 5
5 of 13
Question 5e) The inverse is both linear and a function.Exercise scan
Step 6
6 of 13
Question 5f) The inverse is both linear and a function.Exercise scan
Step 7
7 of 13
Question 6a) The inverse is both linear and a function.Exercise scan
Step 8
8 of 13
Question 6b) The inverse is both linear and a function.Exercise scan
Step 9
9 of 13
Question 6c) The inverse is linear but NOT a function because it fails the vertical line test, in other words, there are more than value of $y$ for a single value of $x$.

Exercise scan

Step 10
10 of 13
Question 6d) The inverse is both linear and a function.Exercise scan
Step 11
11 of 13
Question 6e) The inverse is both linear and a function.Exercise scan
Step 12
12 of 13
Question 6f) The inverse is both linear and a function.Exercise scan
Result
13 of 13
Question 5: all are function and linear

Question 6:

a) function, linear

b) function, linear. The function and its inverse are the same graph

c) NOT a function, linear.

d) function, linear

e) function linear. The function and its inverse are the same graph.

f) function, linear

Exercise 8
Step 1
1 of 5
a) $left{ (-1,2), (1,4), (2,6), (3,8) right}$

Domain of this function is the set of x- coordinates, and range is the set of y-coordinates:v

Domain=$left{-1,1,2,3 right}$

Range=$left{2,4,6,8 right}$

Inverse function we can get if switch the x- and y-coordinates
of each points. So, inverse function is:

$left{ (2,-1), (4,1), (6,2), (8,3)right}$

Domain of inverse function is $left{2,4,6,8 right}$

Range of inverse function is $left{-1,1,2,3 right}$

We can conclude that: domain of the function is a range of inverse function and range of function is a domain of inverse function.

see graph: blue points is the point of the function, and red points is the point of it’s inverseExercise scan
Step 2
2 of 5
b)Function is $left{ (-4,6), (-2,3), (1,8), (5,8) right}$

Domain of this function is the set of x- coordinates, and range is the set of y-coordinates:v

Domain=$left{-4,-2,1,5 right}$

Range=$left{6,3,8 right}$

Inverse relation we can get if switch the x- and y-coordinates
of each points. So, inverse relation is:

$left{ (6,-4), (3,-2), (8,1), (8,5)right}$

Inverse relation is not a function because for 8 value of domain we get two values of range 1 and 5.

Domain of inverse relation is $left{6,3,8 right}$

Range of inverse function is $left{-4,-2,1,5 right}$

see graph: blue points is the point of the function, and red points is the point of it’s inverseExercise scan
Step 3
3 of 5
a) $f(x)=1-3x$

This is a linear function
Domain=$left{xin R right}$

Range=$left{yin R right}$

Inverse function we get on this way:

$y=1-3x$ subtract 1 from both sides

$y-1=-3x$ divide both sides by -3

$dfrac{y-1}{-3}=x$

$x=dfrac{1-y}{3}$

Inverse function is $f^{-1}(x)=dfrac{1-x}{3}$
Domain of inverse function is $left{xin R right}$

Range of inverse function is $left{yin R right}$

see graph: blue points is the point of the function, and red points is the point of it’s inverseExercise scan
Step 4
4 of 5
c) Function is $left{ (-4,-3), (-3,-2), (-2,-2), (-1,-2), (0,-1), (1,-1), (2,0), (3,1), (4,2), (5,1) right}$

Domain of this function is the set of x- coordinates, and range is the set of y-coordinates:v

Domain=$left{-4,-3,-2,-1,0,1,2,3,4,5right}$

Range=$left{-3,-2,-1,0,1,2,1 right}$

Inverse relation we can get if switch the x- and y-coordinates
of each points. So, inverse relation is:

$left{ (-3,-4),(-2,-3),(-2,-2),(-2,-1),(-1,0),(-1,1),(0,2),(1,3),(2,4),(1,5)right}$

Inverse relation is not a function because for -2 value of domain we get two values of range -1 and -2.

Domain of inverse relation is $left{-3,-2,-1,0,1,2 right}$

Range of inverse function is $left{-4,-3,-2,-1,0,1,2,3,4,5 right}$

see graph: blue points is the point of the function, and red points is the point of it’s inverseExercise scan
Result
5 of 5
a) ${ (2,-1),;(4,1),;(6,2),;(8,3)}$

function: domain = ${-1,;1,;2,;3}$ , range = ${ 2,;4,;6,;8}$

inverse: domain = ${2,;4,;6,;8}$, range = ${-1,;1,;2,;3}$

The domain and range are interchanged.

b) ${ (6,-4),;(3,-2),;(8,1),;(8,5)}$

Function: domain = ${-4,;-2,;1,;5}$ , range = ${3,;6,;8}$

inverse: domain = ${3,;6,;8}$, range = ${-4,;-2,;1,;5}$

The domain and range are interchanged.

c) $f^{-1}(x)=dfrac{1}{3}(1-x)$

Function: domain = ${xinbold{R}}$ , range = ${yinbold{R}}$

inverse: domain = ${ xinbold{R}}$ , range = ${ yinbold{R}}$

The domain and range are identical for both function and inverse.

d) ${(-3,-4),(-2,-3),(-2,-2),(-2,-1),(-1,0),(-1,1), (0,2),(1,3),(2,4)(1,5)}$

function: domain = ${ 0,pm1,;pm2,;pm3,;pm4,5}$ , range =${0,pm1,;pm2,;-3}$

inverse: domain = ${0,pm1,;pm2,;,-3}$ , range = ${ 0,pm1,;pm2,;pm3,;pm4,;5}$

The domain and range are interchanged.

Exercise 9
Step 1
1 of 6
a) In the equation $f(x)=5x-2$ the operations on x are as follows: add 2 to both side and then divide both side by 5

$f(x)=5x-2$ add 2 to a both sides

$f(x)+2=5x$ divide both side by 5

$dfrac{f(x)+2}{5}=x$

Inverse function is $f^{-1}(x)=dfrac{x+2}{5}$ or $f^{-1}(x)=dfrac{1}{5}x+dfrac{2}{5}$

b) see graph on the right side

c) The inverse is a function because any vertical line drawn on the graph intersects the graph at onlyone point. This is the graph of a function. The graph of $f^{-1}(x)=dfrac{1}{5}x+dfrac{2}{5}$ is a straight line with slope $dfrac{1}{5}$ .

d) The common point of the function and it’s inverse is point A(0.5, 0.5) (see graph)

e)

Slope of the function $f(x)=5x-2$ is 5

Slope of the function $f^{-1}(x)=dfrac{1}{5}x+dfrac{2}{5}$ si $dfrac{1}{5}$

We can conclude that: slopes are reciprocals of each other

see graph: blue points is the point of the function, and red points is the point of it’s inverseExercise scan
Step 2
2 of 6
a) In the equation $g(x)=-dfrac{1}{2}x+3$ the operations on x are as follows: subtract 3 from the both sides and then multiply both side by $-2$

$g(x)=-dfrac{1}{2}x+3$ subtract 3 from the both sides

$g(x)-3=-dfrac{1}{2}x$ multiply both both side by -2

$-2(g(x)-3)=x$ simplify

$-2g(x)+6=x$

Inverse function is $g^{-1}(x)=-2x+6$

b) see graph on the right side

c) The inverse is a function because any vertical line drawn on the graph intersects the graph at onlyone point. This is the graph of a function. The graph of $g^{-1}(x)=-2x+6$ is a straight line with slope $-2$ .

d) The common points of the function and its inverse is point A(2,2) (see graph)

e)

Slope of the function $g(x)=-dfrac{1}{2}x+3$ is $-dfrac{1}{2}$

Slope of the function $g^{-1}(x)=-2x+6$ si $-2$

We can conclude that: slopes are reciprocals of each other

see graph:Exercise scan
Step 3
3 of 6
a) In the equation $h(x)=2x-1$ the operations on x are as follows: add 1 to both side and then divide both side by 2

$h(x)=2x-1$ add 1 to a both sides

$h(x)+1=2x$ divide both side by 2

$dfrac{h(x)+1}{2}=x$

Inverse function is $h^{-1}(x)=dfrac{x+1}{2}$ or $h^{-1}(x)=dfrac{1}{2}x+dfrac{1}{2}$

b) see graph on the right side

c) The inverse is a function because any vertical line drawn on the graph intersects the graph at onlyone point. This is the graph of a function. The graph of $h^{-1}(x)=dfrac{1}{2}x+dfrac{1}{2}$ is a straight line with slope $dfrac{1}{2}$ .

d) The common point of the function and it’s inverse is the point A(1,1) (see graph)

e)

Slope of the function $h(x)=2x-1$ is 2

Slope of the function $h^{-1}(x)=dfrac{1}{2}x+dfrac{1}{2}$ si $dfrac{1}{2}$

We can conclude that: slopes are reciprocals of each other

see graph: blue points is the point of the function, and red points is the point of it’s inverseExercise scan
Step 4
4 of 6
a) In the equation $f(x)=6-x$ the operations on x are as follows: subtract 6 from the both side and then multiply both side by -1

$p(x)=6-x$ subtract 6 from the both sides

$p(x)-6=-x$ multiply both side by -1

$-1(p(x)-6)=x$ simplify

$$
-p(x)+6=x
$$

Inverse function is $p^{-1}(x)=-x+6$

b) see graph on the right side

c) The inverse is a function because any vertical line drawn on the graph intersects the graph at only one point. This is the graph of a function. The graph of $p^{-1}(x)=-x+6$ is a straight line with slope $-1$

d) The common points of the function and its inverse is each points of graphs

Function and it’s inverse are the same

e)

Slope of the function $p(x)=6-x$ is -1

Slope of the function $p^{-1}(x)=-x+6$ is $-1$

We can conclude that: slopes are the same

see graph: blue points is the point of the function, and red points is the point of it’s inverseExercise scan
Step 5
5 of 6
a) Function is $q(x)=2$. This is the line $y=2$

Inverse $q^{-1}$ of this function is relation $x=2$. This is not a function , because for one value $x=2$ we get differente values of $y$. Domain of this relation is $left{xin R| x=2 right}$, and range of this relation is $left{yin R right}$

b) see graph on the right side

c)The graph of $q^{-1}$ is not a function, but it is a straight line.

d)The common points of the function $q(x)=2$ and it’s inverse relation $x=2$ is point A(2,2) (see graph)

e) Slope of the function $q(x)=2$ is 0

Slope of the relation $x=2$ is undefined

see graph: blue points is the point of the function, and red points is the point of it’s inverseExercise scan
Result
6 of 6
a) $f^{-1}(x)=dfrac{1}{5}(x+2)$

b) The graph has been plotted in the answer.

c) The function is linear (straight line) with slope $ne$ 0

d) $left(dfrac{1}{2},dfrac{1}{2}right)$

e) The slopes are reciprocal of each other.

f) Answers are the following

a) $g^{-1}(x)=2(3-x)$

function is linear with slope $ne$ 0

(2,2)

slopes are reciprocals of each other

b) $h^{-1}(x)=dfrac{1}{2}(x+1)$

function is linear with slope $ne$ 0

(1,1) ; slopes are reciprocal of each other.

c) $p^{-1}(x)=6-x$

function is linear with slope $ne$ 0

all points on the graph; slopes are the same.

d) $q^{-1}:x=2$

not a function (slope is zero so the inverse is vertical line)

(2,2) ; slopes are 0 and undefined

Exercise 10
Step 1
1 of 7
There is $g(t)=3t-2$.

a) To find $g(13)$ , plug in 13 wherever $t$ occures in the equation of $g(t)$ and simplify to get $g(t)$

$g(13)=3cdot13-2=39-2=37$

Step 2
2 of 7
b) To find $g(7)$ , plug in 7 wherever $t$ occures in the equation of $g(t)$ and simplify to get $g(t)$

$g(7)=3cdot7-2=21-2=19$

Step 3
3 of 7
c) To find $dfrac{g(13)-g(7)}{13-7}$ , plug in g(13) and g(7) using parts a) and b) and then simplify:

$$
dfrac{g(13)-g(7)}{13-7}=dfrac{37-19}{13-7}=dfrac{18}{6}=3
$$

Step 4
4 of 7
d) The first, we need find inverse function $g^{-1}(x)$, and then plug in 13 wherever $t$ occures in the equation of $g^{-1}(t)$ and simplify to get $g^{-1}(t)$

In the equation $g(t)=3t-2$ the operations on $t$ are as follows: add 2 to both sides and then divide both sides by 3:

$g(t)=3t-2$ add 2 to both sides

$g(t)+2=3t$ divide both sides by 3

$dfrac{g(t)+2}{3}=t$

Inverse function is $g^{-1}(t)=dfrac{t+2}{3}$

Now we can determine $g^{-1}(13)$. plug in 13 wherever $t$ occures in the equation of $g^{-1}(t)$

$g^{-1}(13)=dfrac{13+2}{3}=dfrac{15}{3}=5$

Step 5
5 of 7
e) Use part d) we get $g^{-1}(t)=dfrac{t+2}{3}$

Now we can determine $g^{-1}(7)$. plug in 7 wherever $t$ occures in the equation of $g^{-1}(t)$

$g^{-1}(7)=dfrac{7+2}{3}=dfrac{9}{3}=3$

Step 6
6 of 7
To find $dfrac{g^{-1}(13)-g^{-1}(7)}{13-7}$ , plug in $g^{-1}(13)$ and $g^{-1}(7)$ using parts d) and e) and then simplify:

$$
dfrac{g^{-1}(13)-g^{-1}(7)}{13-7}=dfrac{5-3}{13-7}=dfrac{2}{6}=dfrac{1}{3}
$$

Result
7 of 7
a) 37

b) 19

c) 3

d) 5

e) 3

f) $dfrac{1}{3}$

Exercise 11
Step 1
1 of 3
$bold{Concept:}$ If a line $f(x)$ passes through points $(x_1,y_1)$ and $(x_2,y_2)$, then the slope of the line is

$$
m=dfrac{y_2-y_1}{x_2-x_1}=dfrac{f(x_2)-f(x_1)}{x_2-x_1}
$$

Step 2
2 of 3
$bold{Solution:}$ By inspection, parts (c) represents the slope of the line $g(t)$ evaluated at $x_1=7$ and $x_2=13$. Similarly, part (f) represents the slope of $g^{-1}(t)$
Result
3 of 3
It represents the slope of $g(t)$ and $g^{-1}(t)$ respectively.
Exercise 12
Step 1
1 of 6
a)Let $x$ be a Celsius temperature. Shirelle uses a simpler rule to convert from Celsius to Fahrenheit: $f(x)=2x+30$
Step 2
2 of 6
b) In the equation $f(x)=2x+30$ the operations on $x$ are as follows: subtract 30 from the both sides and then divide both side by 2:

$f(x)=2x+30$ subrtact 30 from the both sides

$f(x)-30=2x$ divide both side by 2

$dfrac{f(x)-30}{2}=x$

Inverse function is $f^{-1}(x)=dfrac{x-30}{2}$ or $f^{-1}(x)=dfrac{1}{2}x-15$

This rule use a Canadian visiting the United States

Step 3
3 of 6
c) In part b) is determined $f^{-1}(x)=dfrac{1}{2}x-15$
Step 4
4 of 6
d) Using function notation $f(x)=2x+30$ to express this temperature in degrees Fahrenheit we get:

$$
f(14)=2cdot14+30=28+30=58^{o}F
$$

Step 5
5 of 6
e) Using function notation $f^{-1}(x)=dfrac{1}{2}x-15$ to express this temperature in degrees Celsius we get:

$$
f^{-1}(70)=dfrac{1}{2}cdot70-15=35-15=20^{o}C
$$

Result
6 of 6
a) $f(x)=2x+30$

b) subtract 30 from both sides and divide by 2 ; a Canadian visiting the United States

c) $f^{-1}(x)=dfrac{x-30}{2}$

d) $f(14)=58^circ$ F

e) $f^{-1}(70)=20^circ$ C

Exercise 13
Step 1
1 of 7
Ben uses this rule to convert centimetres to inches: Multiply by 4 and then divide by 10

Let $x$ represent centimeters. Then, Ben’s rule is $g(x)=dfrac{4x}{10}$

Step 2
2 of 7
a) We have $g(x)=dfrac{4x}{10}$

Let $g^{-1}$ be the method for converting inches to centimeters, according to rule: multiply by 10 and then divide by 4.

$g(x)=dfrac{4x}{10}$ multiply both side by 10

$10g(x)=4x$ divide both side by 4

$dfrac{10g(x)}{4}=x$

So, inverse is $g^{-1}(x)=dfrac{10x}{4}$

Step 3
3 of 7
b) $g^{-1}$ is the method for converting inches to centimeters, and this rule use a Canadian visiting the U.S.
Step 4
4 of 7
c) Ben uses rule multiply by 4 and then divide by 10, this rule is $g(x)=dfrac{4x}{10}$

Now, we need determine rule $g^{-1}(x)$

$g(x)=dfrac{4x}{10}$ multiply both side by 10

$10g(x)=4x$ divide both side by 4

$dfrac{10g(x)}{4}=x$

So, inverse is $g^{-1}(x)=dfrac{10x}{4}$

Step 5
5 of 7
d) Using function notation $g(x)=dfrac{4x}{10}$ to represent 15cm in inches we get:

$g(x)=dfrac{4x}{10}=dfrac{4cdot15}{10}=dfrac{60}{10}=6$ inches

Step 6
6 of 7
e)We know that 1 ft=12 in , that means
5ft 10 in =$5cdot12+10$in=60+10 in=70 in

Using function notation $g^{-1}(x)=dfrac{10x}{4}$ to represent 70 inches in centimeters we get:

$g^{-1}(x)=dfrac{10x}{4}=dfrac{10cdot70}{4}=dfrac{700}{4}=175$ cm

Result
7 of 7
[begin{gathered}
{text{a) Multiply by 10, and then divide it by 4}}{text{.}} hfill \
{text{b) Canadian citizen visiting the USA}}{text{.}} hfill \
{text{c) g(x) = }}frac{{4x}}{{10}};{g^{ – 1}}(x) = frac{{10x}}{4} hfill \
{text{d) g(15) = }}frac{{4(15)}}{{10}} = 6,{text{in}}{text{.}} hfill \
{text{e) }}{{text{g}}^{ – 1}}(70) = frac{{10,(70)}}{4} = 175,{text{cm}} hfill \
end{gathered} ]
Exercise 14
Solution 1
Solution 2
Step 1
1 of 2
Since he mixed up the independent and dependent variable, the correct equation must be the inverse of what he got.

Thus, this is asking for the inverse of $y=2.63x-1.29$

To find the inverse of any function, swap the positions of the variables and solve for $y$

$x=2.63y-1.29$

$2.63y=x+1.29$

$dfrac{2.63y}{2.63}=dfrac{x+1.29}{2.63}$

$y=dfrac{x+1.29}{2.63}$

We need to write it in the form $y=mx+b$

$y=dfrac{1}{2.63}x+dfrac{1.29}{2.63}$

$$
y=0.38x+0.50
$$

Result
2 of 2
$$
y=0.38x+0.50
$$
Step 1
1 of 2
$x=2.63y-1.29$

$x+1.29=2.63y$

$frac{x}{2.63}+frac{1.29}{2.63}=y$

$y=frac{x}{2.63}+frac{1.29}{2.63}$

$$
y=mx+b
$$

Since he mixed up the variables we simply need to exchange the x and y values and then solve for y to put in the form y=mx+b
Result
2 of 2
See equation
Exercise 15
Step 1
1 of 4
a) Let $y$ be Tiffany’s total pay and $x$ is her sales for that week.

payment for hourly work: $8.05(40)$

payment for sales over $$1000$: $0.05(x-1000)$

Thus, the equation describing her weekly earning is

$y=8.05(40)+0.05(x-1000)$

Since number of sales can’t be negative, the domain is $xgeq 0$

Exercise scan

Step 2
2 of 4
b) In function notation, we can write it as:

$f(x)=322+0.05(x-1000)$ ; $xgeq 0$

c) The inverse relation is obtained by switching the position of the variables then solve for $y$

$x=322+0.05(y-1000)$

$0.05(y-1000)=x-322$

$y-1000=dfrac{x-322}{0.05}$

$y=20(x-322)+1000$

Note that the range of the original function must the domain of its inverse.

The original function has a range of ${ yinbold{R};|;ygeq 278}$ because the minimum salary occurs when she has zero sales ($y$-intercept).

So the domain of the inverse must be ${ xinbold{R};|;xgeq 278}$

Exercise scan

Step 3
3 of 4
d) In function notation, the inverse is denoted as $f^{-1}(x)$

$f^{-1}(x)=20(x-322)+1000$ ; $xgeq 278$

e) We must find $x$ such that $f(x)=420$. This is just the value of $f^{-1}(420)$

$f^{-1}(420)=1000+20(420-322)=$2960$

Note that the answer at the back of your book is different because it incorrectly evaluates $8.05(40)=32.2$ instead of 322.

Result
4 of 4
a) graph of $y=32.2+0.05(x-1000)$

b) $f(x)=32.2+0.05(x-1000)$

c) graph of $y=20(x-32.2)+1000$

d) $f^{-1}(x)=1000+20(x-32.2)$

e) $f^{-1}(420)=1000+20(420-322)=$2960$

Exercise 16
Solution 1
Solution 2
Step 1
1 of 1
The ordered pair $(1, 5)$ belongs to a function $f$. Switch the x- and y-coordinates of point we get $(5,1)$ It gives me an inverse $f^{-1}$.

Because (2,1) cannot belong to $f^{-1}$

Step 1
1 of 3
$bold{Concept:}$ If $f(x)$ contains the point $(a,b)$, then $f^{-1}(x)$ must contain the point $(b,a)$
Step 2
2 of 3
$bold{Solution:}$ We are given that $f$ contains $(1,5)$ so $f^{-1}$ must contain $(5,1)$ and not $(2,1)$. Since $f$ is a function, it cannot have both $(1,5)$ and $(1,2)$.
Result
3 of 3
$f^{-1}$ must contain $(5,1)$ and not $(2,1)$. Since $f$ is a function, it cannot have both $(1,5)$ and $(1,2)$ , therefore, $(2,1)$ cannot belong to $f^{-1}$
Exercise 17
Step 1
1 of 2
There is $f(x)=k(2+x)$. We need find the value $k$ if $f^{-1}(-2)=-3$.

The first, we need find $f^{-1}(x)$.

In the equation $f(x)=k(2+x)$ the operations on $x$ are as follows: divide both sides by $k$, and then subtract 2 from the both sides.

$f(x)=k(2+x)$ divide both sides by $k$

$dfrac{f(x)}{k}=2+x$ subtract 2 from the both sides

$dfrac{f(x)}{k}-2=x$

Inverse function is $f^{-1}(x)=dfrac{x}{k}-2$

To find value $k$ plug in -2 in to $f^{-1}(x)=dfrac{x}{k}-2$ and solve for $k$

$f^{-1}(-2)=dfrac{-2}{k}-2=-3$ add 2 to both sides

$dfrac{-2}{k}=-3+2$

$dfrac{-2}{k}=-1$ multiply both sides by $k$

$-2=-k$, or $k=2$

Solution is $k=2$.

Function is $f(x)=2(2+x)$

Result
2 of 2
$$
k=2
$$
Exercise 18
Step 1
1 of 1
Exercise scan
Exercise 19
Step 1
1 of 2
A function is said to be a self-inverse if $f(x)=f^{-1}(x)$ for all $x$ in the domain.

Example1: Function $f(x)=dfrac{1}{x}, xne0$ is a self-inverse.

check:

$f(x)=dfrac{1}{x}$ multiply both sides by x

$xcdot f(x)=1$ divide both sides by $f(x)ne0$

$x=dfrac{1}{f(x)}$

Inverse function is $f^{-1}(x)=dfrac{1}{x}$.

We can conclude $f(x)=f^{-1}(x)$, so $f(x)$ is a self-inverse

Example 2: Function $g(x)=3-x$ is a self-inverse.

check:

$g(x)=3-x$ subtract from the both sides 3

$g(x)-3=-x$ multiply both sides by -1

$-1(g(x)-3)=x$ simlify

$$
3-g(x)=x
$$

Inverse function is $g^{-1}(x)=3-x$.

We can conclude $g(x)=g^{-1}(x)$, so $g(x)$ is a self-inverse

Example 3: Function $h(x)=x$, is a self-inverse.

check:

$h(x)=x$

$$
x=h(x)
$$

Inverse function is $h^{-1}(x)=x$.

We can conclude $h(x)=h^{-1}(x)$, so $h(x)$ is a self-inverse

Result
2 of 2
Examples:

$y=dfrac{1}{x}$ , $y=3-x$, $y=x$

Exercise 20
Step 1
1 of 5
$f(x)= 3x+4$

Substitute

$f(x)implies (x)$

$x implies f^{-1}(x)$

Thus,

$x = 3 f^{-1}(x)+4$

Remember this concept:

If $f^{-1}(x)$ is the inverse of $f(x)$, then

$f(f^{-1}(x))=x$

To find the inverse of a function $f(x)$, do the following substitutions:

$f(x) implies x$

$x implies f^{-1}(x)$

Step 2
2 of 5
$3f^{-1}(x)=x-4$

$dfrac{3f^{-1}(x)}{3}=dfrac{x-4}{3}$

$$
f^{-1}(x)=dfrac{x-4}{3}
$$

Then solve for $f^{-1}(x)$.
Step 3
3 of 5
$f(f^{-1}(x))=3left(dfrac{x-4}{3}right)+4$

$f(f^{-1}(x))=x-4+4$

$$
f(f^{-1}(x))=x
$$

To check whether this is indeed the inverse function, find $f(f^{-1}(x))$
Step 4
4 of 5
$f^{-1}(x)=g(x)=dfrac{x-4}{3}$

$x=dfrac{g^{-1}(x)-4}{3}$

$3x = g^{-1}(x)-4$

$g^{-1}(x)=3x+4$

Thus

$$
f^{-1}[(f^{-1})(x)]=f(x)=3x+4
$$

Now let $g(x)=f^{-1}(x)$. We will check if the inverse of $g(x)$ will result in the original function $f(x)$.
Result
5 of 5
$$
f^{-1}[(f^{-1})(x)]=f(x)=3x+4
$$
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