Books(current) Courses (current) Earn đŸ’° Log in(current)

Chapter 1

Functions and Models

Educators

BS
MP
MM
SB
KV
+ 3 more educators

Problem 1

If $f(x)=x+\sqrt{2-x}$ and $g(u)=u+\sqrt{2-u},$ is it true that $f=g ?$

Check back soon!

Problem 2

If
$$f(x)=\frac{x^{2}-x}{x-1} \quad \text { and } \quad g(x)=x$$
is it true that $f=g ?$

Check back soon!

Problem 3

The graph of a function $f$ is given.
(a) State the value of $f(1) .$
(b) Estimate the value of $f(-1)$
(c) For what values of $x$ is $f(x)=1 ?$
(d) Estimate the value of $x$ such that $f(x)=0$
(e) State the domain and range of $f$
(f) On what interval is $f$ increasing?

BS
Brent S.
Numerade Educator

Problem 4

The graphs of $f$ and $g$ are given.
(a) State the values of $f(-4)$ and $g(3)$
(b) For what values of $x$ is $f(x)=g(x) ?$
(c) Estimate the solution of the equation $f(x)=-1$
(d) On what interval is $f$ decreasing?
(e) State the domain and range of $f$
(f) State the domain and range of $g .$

Check back soon!

Problem 5

Figure 1 was recorded by an instrument operated by the Cali- fornia Department of Mines and Geology at the University Hospital of the University of Southern California in Los Angeles. Use it to estimate the range of the vertical ground acceleration function at USC during the Northridge earthquake.

Check back soon!

Problem 6

In this section we discussed examples of ordinary, everyday functions: Population is a function of time, postage cost is a function of weight, water temperature is a function of time. Give three other examples of functions from everyday life that are described verbally. What can you say about the domain and range of each of your functions? If possible, sketch a rough graph of each function.

MP
Matt P.
Numerade Educator

Problem 7

$7-10$ Determine whether the curve is the graph of a function of $x .$ If it is, state the domain and range of the function.

MM
Marcus M.
Numerade Educator

Problem 8

$7-10$ Determine whether the curve is the graph of a function of $x .$ If it is, state the domain and range of the function.

SB
Shannon B.
Numerade Educator

Problem 9

$7-10$ Determine whether the curve is the graph of a function of $x .$ If it is, state the domain and range of the function.

Check back soon!

Problem 10

$7-10$ Determine whether the curve is the graph of a function of $x .$ If it is, state the domain and range of the function.

Check back soon!

Problem 11

The graph shown gives the weight of a certain person as a function of age. Describe in words how this person's weight varies over time. What do you think happened when this person was 30 years old?

Check back soon!

Problem 12

The graph shows the height of the water in a bathtub as a function of time. Give a verbal description of what you think happened.

Check back soon!

Problem 13

You put some ice cubes in a glass, fill the glass with cold water, and then let the glass sit on a table. Describe how the temperature of the water changes as time passes. Then sketch a rough graph of the temperature of the water as a function of the elapsed time.

Check back soon!

Problem 14

Three runners compete in a 100 -meter race. The graph depicts the distance run as a function of time for each runner. Describe in words what the graph tells you about this race. Who won the race? Did each runner finish the race?

KV
Kurt V.
Numerade Educator

Problem 15

The graph shows the power consumption for a day in September in San Francisco. (P is measured in megawatts; $t$ is measured in hours starting at midnight.)
(a) What was the power consumption at 6 AM? At 6 PM?
(b) When was the power consumption the lowest? When was it the highest? Do these times seem reasonable?

Check back soon!

Problem 16

Sketch a rough graph of the number of hours of daylight as a function of the time of year.

Check back soon!

Problem 17

Sketch a rough graph of the outdoor temperature as a function of time during a typical spring day.

Check back soon!

Problem 18

Sketch a rough graph of the market value of a new car as a function of time for a period of 20 years. Assume the car is well maintained.

Check back soon!

Problem 19

Sketch the graph of the amount of a particular brand of coffee sold by a store as a function of the price of the coffee.

Check back soon!

Problem 20

You place a frozen pie in an oven and bake it for an hour. Then you take it out and let it cool before eating it. Describe how the temperature of the pie changes as time passes. Then sketch a rough graph of the temperature of the pie as a function of time.

SL
Samuel L.
Numerade Educator

Problem 21

A homeowner mows the lawn every Wednesday afternoon. Sketch a rough graph of the height of the grass as a function of time over the course of a four-week period.

Check back soon!

Problem 22

An airplane takes off from an airport and lands an hour later at another airport, 400 miles away. If $t$ represents the time in minutes since the plane has left the terminal building, let $x(t)$ be the horizontal distance traveled and $y(t)$ be the altitude of the plane.
(a) Sketch a possible graph of $x(t) .$
(b) Sketch a possible graph of $y(t) .$
(c) Sketch a possible graph of the ground speed.
(d) Sketch a possible graph of the vertical velocity.

Robert H.
Numerade Educator

Problem 23

The number $N$ (in millions) of US cellular phone subscribers is shown in the table. (Midyear estimates are given.)
$$\begin{array}{|c|c|c|c|c|c|}\hline t & {1996} & {1998} & {2000} & {2002} & {2004} & {2006} \\ \hline N & {44} & {69} & {109} & {141} & {182} & {233} \\ \hline\end{array}$$
(a) Use the data to sketch a rough graph of $N$ as a function of $t$
(b) Use your graph to estimate the number of cell-phone subscribers at midyear in 2001 and $2005 .$

Check back soon!

Problem 24

Temperature readings $T$ (In$^{\circ} \mathrm{F}$) were recorded every two hours from midnight to $2 : 00 \mathrm{PM}$ in Phoenix on September $10,2008$ The time $t$ was measured in hours from midnight.
$$\begin{array}{|c|c|c|c|c|c|c|c|c|}\hline t & {0} & {2} & {4} & {6} & {8} & {10} & {12} & {14} \\ \hline T & {82} & {75} & {74} & {75} & {84} & {90} & {93} & {94} \\ \hline\end{array}$$
(a) Use the readings to sketch a rough graph of $T$ as a function of $t$ .
(b) Use your graph to estimate the temperature at $9 : 00$ AM.

GD
Gilbert D.
Numerade Educator

Problem 25

If $f(x)=3 x^{2}-x+2$ find $f(2), \quad f(-2), f(a), f(-a)$ $f(a+1), 2 f(a), f(2 a), f\left(a^{2}\right),[f(a)]^{2}$ and $f(a+h)$

Check back soon!

Problem 26

A spherical balloon with radius $r$ inches has volume $V(r)=\frac{4}{3} \pi r^{3} .$ Find a function that represents the amount of air required to inflate the balloon from a radius of $r$ inches to a radius of $r+1$ inches.

Check back soon!

Problem 27

$27-30$ Evaluate the difference quotient for the given function. Simplify your answer.
$$f(x)=4+3 x-x^{2}, \quad \frac{f(3+h)-f(3)}{h}$$

Check back soon!

Problem 28

$27-30$ Evaluate the difference quotient for the given function. Simplify your answer.
$$f(x)=x^{3}, \quad \frac{f(a+h)-f(a)}{h}$$

Check back soon!

Problem 29

$27-30$ Evaluate the difference quotient for the given function. Simplify your answer.
$$f(x)=\frac{1}{x}, \quad \frac{f(x)-f(a)}{x-a}$$

Check back soon!

Problem 30

$27-30$ Evaluate the difference quotient for the given function. Simplify your answer.
$$f(x)=\frac{x+3}{x+1}, \quad \frac{f(x)-f(1)}{x-1}$$

Check back soon!

Problem 31

$31-37$ Find the domain of the function.
$$f(x)=\frac{x+4}{x^{2}-9}$$

Check back soon!

Problem 32

$31-37$ Find the domain of the function.
$$f(x)=\frac{2 x^{3}-5}{x^{2}+x-6}$$

Check back soon!

Problem 33

$31-37$ Find the domain of the function.
$$f(t)=\sqrt[3]{2 t-1}$$

Check back soon!

Problem 34

$31-37$ Find the domain of the function.
$$g(t)=\sqrt{3-t}-\sqrt{2+t}$$

Check back soon!

Problem 35

$31-37$ Find the domain of the function.
$$h(x)=\frac{1}{\sqrt[4]{x^{2}-5 x}}$$

Check back soon!

Problem 36

$31-37$ Find the domain of the function.
$$f(u)=\frac{u+1}{1+\frac{1}{u+1}}$$

Check back soon!

Problem 37

$31-37$ Find the domain of the function.
$$F(p)=\sqrt{2-\sqrt{p}}$$

Check back soon!

Problem 38

Find the domain and range and sketch the graph of the function $h(x)=\sqrt{4-x^{2}}$

Check back soon!

Problem 39

$39-50$ Find the domain and sketch the graph of the function.
$$f(x)=2-0.4 x$$

Check back soon!

Problem 40

$39-50$ Find the domain and sketch the graph of the function.
$$F(x)=x^{2}-2 x+1$$

Check back soon!

Problem 41

$39-50$ Find the domain and sketch the graph of the function.
$$f(t)=2 t+t^{2}$$

Check back soon!

Problem 42

$39-50$ Find the domain and sketch the graph of the function.
$$H(t)=\frac{4-t^{2}}{2-t}$$

Check back soon!

Problem 43

$39-50$ Find the domain and sketch the graph of the function.
$$g(x)=\sqrt{x-5}$$

Check back soon!

Problem 44

$39-50$ Find the domain and sketch the graph of the function.
$$F(x)=|2 x+1|$$

Check back soon!

Problem 45

$39-50$ Find the domain and sketch the graph of the function.
$$G(x)=\frac{3 x+|x|}{x}$$

Check back soon!

Problem 46

$39-50$ Find the domain and sketch the graph of the function.
$$g(x)=|x|-x$$

Check back soon!

Problem 47

$39-50$ Find the domain and sketch the graph of the function.
$$f(x)=\left\{\begin{array}{ll}{x+2} & {\text { if } x<0} \\ {1-x} & {\text { if } x \geqslant 0}\end{array}\right.$$

Check back soon!

Problem 48

$39-50$ Find the domain and sketch the graph of the function.
$$f(x)=\left\{\begin{array}{ll}{3-\frac{1}{2} x} & {\text { if } x \leqslant 2} \\ {2 x-5} & {\text { if } x>2}\end{array}\right.$$

Check back soon!

Problem 49

$39-50$ Find the domain and sketch the graph of the function.
$$f(x)=\left\{\begin{array}{ll}{x+2} & {\text { if } x \leqslant-1} \\ {x^{2}} & {\text { if } x>-1}\end{array}\right.$$

Check back soon!

Problem 50

$39-50$ Find the domain and sketch the graph of the function.
$$f(x)=\left\{\begin{array}{ll}{x+9} & {\text { if } x<-3} \\ {-2 x} & {\text { if }|x| \leqslant 3} \\ {-6} & {\text { if } x>3}\end{array}\right.$$

Check back soon!

Problem 51

\begin{equation}
\begin{array}{l}{51-56 \text { Find an expression for the function whose graph is the }} \\ {\text { given curve. }}\end{array}
\end{equation}
The line segment joining the points $(1,-3)$ and $(5,7)$

Check back soon!

Problem 52

\begin{equation}
\begin{array}{l}{51-56 \text { Find an expression for the function whose graph is the }} \\ {\text { given curve. }}\end{array}
\end{equation}
The line segment joining the points $(-5,10)$ and $(7,-10)$

Check back soon!

Problem 53

\begin{equation}
\begin{array}{l}{51-56 \text { Find an expression for the function whose graph is the }} \\ {\text { given curve. }}\end{array}
\end{equation}
The bottom half of the parabola $x+(y-1)^{2}=0$

Check back soon!

Problem 54

\begin{equation}
\begin{array}{l}{51-56 \text { Find an expression for the function whose graph is the }} \\ {\text { given curve. }}\end{array}
\end{equation}
The top half of the circle $x^{2}+(y-2)^{2}=4$

Check back soon!

Problem 55

$51-56$ Find an expression for the function whose graph is the given curve.

Check back soon!

Problem 56

$51-56$ Find an expression for the function whose graph is the given curve.

Check back soon!

Problem 57

\begin{equation}
\begin{array}{l}{57-61 \text { Find a formula for the described function and state its }} \\ {\text { domain. }}\end{array}
\end{equation}
A rectangle has perimeter 20 $\mathrm{m} .$ Express the area of the rect- angle as a function of the length of one of its sides.

Check back soon!

Problem 58

\begin{equation}
\begin{array}{l}{57-61 \text { Find a formula for the described function and state its }} \\ {\text { domain. }}\end{array}
\end{equation}
A rectangle has area 16 $\mathrm{m}^{2} .$ Express the perimeter of the rectangle as a function of the length of one of its sides.

Check back soon!

Problem 59

\begin{equation}
\begin{array}{l}{57-61 \text { Find a formula for the described function and state its }} \\ {\text { domain. }}\end{array}
\end{equation}
Express the area of an equilateral triangle as a function of the length of a side.

Check back soon!

Problem 60

\begin{equation}
\begin{array}{l}{57-61 \text { Find a formula for the described function and state its }} \\ {\text { domain. }}\end{array}
\end{equation}
Express the surface area of a cube as a function of its volume.

Check back soon!

Problem 61

\begin{equation}
\begin{array}{l}{57-61 \text { Find a formula for the described function and state its }} \\ {\text { domain. }}\end{array}
\end{equation}
An open rectangular box with volume 2 $\mathrm{m}^{3}$ has a square base. Express the surface area of the box as a function of the length of a side of the base.

Check back soon!

Problem 62

A Norman window has the shape of a rectangle surmounted by a semicircle. If the perimeter of the window is 30 $\mathrm{ft}$ , express the area $A$ of the window as a function of the width $x$ of the window.

Check back soon!

Problem 63

A box with an open top is to be constructed from a rectangular piece of cardboard with dimensions 12 in. by 20 in. by cutting out equal squares of side $x$ at each corner and then folding up the sides as in the figure. Express the volume $V$ of the box as a function of $X .$

Check back soon!

Problem 64

A cell phone plan has a basic charge of $\$ 35$ a month. The plan includes 400 free minutes and charges 10 cents for each additional minute of usage. Write the monthly cost $C$ as a function of the number $x$ of minutes used and graph $C$ as a function of $x$ for 0$\leqslant x \leqslant 600 .$

Check back soon!

Problem 65

In a certain state the maximum speed permitted on freeways is 65 mi/h and the minimum speed is 40 $\mathrm{mi} / \mathrm{h}$ . The fine for violating these limits is $\$ 15$ for every mile per hour above the maximum speed or below the minimum speed. Express the amount of the fine $F$ as a function of the driving speed $x$ and $\operatorname{graph} F(x)$ for 0$\leqslant x \leqslant 100.$

Check back soon!

Problem 66

An electricity company charges its customers a base rate of $\$ 10$ a month, plus 6 cents per kilowatt-hour $(\mathrm{kWh})$ for the first 1200 $\mathrm{kWh}$ and 7 cents per kWh for all usage over 1200 $\mathrm{kWh}$. Express the monthly cost $E$ as a function of the amount $x$ of electricity used. Then graph the function $E$ for 0$\leqslant x \leqslant 2000.$

Check back soon!

Problem 67

In a certain country, income tax is assessed as follows. There is no tax on income up to $\$ 10,000 .$ Any income over $\$ 10,000$ is taxed at a rate of $10 \%,$ up to an income of $\$ 20,000 .$ Any income over $\$ 20,000$ is taxed at 15$\% .$
(a) Sketch the graph of the tax rate $R$ as a function of the income I.
(b) How much tax is assessed on an income of $\$ 14,000 ?$ On $\$ 26,000 ?$
(c) Sketch the graph of the total assessed tax $T$ as a function of the income I.

Check back soon!

Problem 68

The functions in Example 10 and Exercise 67 are called step functions because their graphs look like stairs. Give two other examples of step functions that arise in everyday life.

Check back soon!

Problem 69

$69-70$ Graphs of $f$ and $g$ are shown. Decide whether each function is even, odd, or neither. Explain your reasoning.

Check back soon!

Problem 70

$69-70$ Graphs of $f$ and $g$ are shown. Decide whether each function is even, odd, or neither. Explain your reasoning.

Check back soon!

Problem 71

(a) If the point $(5,3)$ is on the graph of an even function, what other point must also be on the graph?
(b) If the point $(5,3)$ is on the graph of an odd function, what other point must also be on the graph?

Check back soon!

Problem 72

A function $f$ has domain $[-5,5]$ and a portion of its graph is shown.
(a) Complete the graph of $f$ if it is known that $f$ is even.
(b) Complete the graph of $f$ if it is known that $f$ is odd

Check back soon!

Problem 73

$73-78$ Determine whether $f$ is even, odd, or neither. If you have a graphing calculator, use it to check your answer visually.
$$f(x)=\frac{x}{x^{2}+1}$$

Check back soon!

Problem 74

$73-78$ Determine whether $f$ is even, odd, or neither. If you have a graphing calculator, use it to check your answer visually.
$$f(x)=\frac{x^{2}}{x^{4}+1}$$

Check back soon!

Problem 75

$73-78$ Determine whether $f$ is even, odd, or neither. If you have a graphing calculator, use it to check your answer visually.
$$f(x)=\frac{x}{x+1}$$

Check back soon!

Problem 76

$73-78$ Determine whether $f$ is even, odd, or neither. If you have a graphing calculator, use it to check your answer visually.
$$f(x)=x|x|$$

Check back soon!

Problem 77

$73-78$ Determine whether $f$ is even, odd, or neither. If you have a graphing calculator, use it to check your answer visually.
$$f(x)=1+3 x^{2}-x^{4}$$

Check back soon!

Problem 78

$73-78$ Determine whether $f$ is even, odd, or neither. If you have a graphing calculator, use it to check your answer visually.
$$f(x)=1+3 x^{3}-x^{5}$$

Check back soon!

Problem 79

If $f$ and $g$ are both even functions, is $f+g$ even? If $f$ and $g$ are both odd functions, is $f+g$ odd? What if $f$ is even and $g$ is odd? Justify your answers.

Check back soon!

Problem 80

If $f$ and $g$ are both even functions, is the product $f g$ even? If $f$ and $g$ are both odd functions, is $f g$ odd? What if $f$ is even and $g$ is odd? Justify your answers.

Check back soon!