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Calculus

Soo T. Tan

Chapter 5

Applications of the Definite Integral - all with Video Answers

Educators


Section 1

Areas Between Curves

02:02

Problem 1

Find the area of the shaded region.

Suman Saurav Thakur
Suman Saurav Thakur
Numerade Educator
02:02

Problem 2

Find the area of the shaded region.

Suman Saurav Thakur
Suman Saurav Thakur
Numerade Educator
02:02

Problem 3

Find the area of the shaded region.

Suman Saurav Thakur
Suman Saurav Thakur
Numerade Educator
02:02

Problem 4

Find the area of the shaded region.

Suman Saurav Thakur
Suman Saurav Thakur
Numerade Educator
02:02

Problem 5

Find the area of the shaded region.

Suman Saurav Thakur
Suman Saurav Thakur
Numerade Educator
02:02

Problem 6

Find the area of the shaded region.

Suman Saurav Thakur
Suman Saurav Thakur
Numerade Educator
01:37

Problem 7

Energy experts disagree about when global oil production will begin to decline. In the following figure, the function $f$ gives the annual world oil production in billions of barrels from 1980 to 2050 according to the
U.S. Department of Energy projection. The function $g$ gives the world oil production in billions of barrels per year over the same period according to longtime petroleum geologist Colin Campbell. Find an expression in terms of definite integrals involving $f$ and $g$ giving the shortfall in the total oil production over the period in question heeding Campbell's dire warnings.

Dharmendra Jain
Dharmendra Jain
Numerade Educator
02:03

Problem 8

The rate of change of the revenue of Company $A$ over the (time) interval $[0, T]$ is $f(t)$ dollars per week, whereas the rate of change of the revenue of Company $B$ over the same period is $g(t)$ dollars per week. Suppose the graphs of $f$ and $g$ are as depicted in the following figure. Find an expression in terms of definite integrals involving $f$ and $g$ giving the additional revenue that Company $B$ will have over Company $A$ in the period $[0, T]$.

Dharmendra Jain
Dharmendra Jain
Numerade Educator
03:25

Problem 9

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=x^{2}+3, \quad y=x+1, \quad x=-1, \quad x=1$

Gregory Higby
Gregory Higby
Numerade Educator
03:21

Problem 10

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=x^{3}+1, \quad y=x-1, \quad x=-1, \quad x=1$

Gregory Higby
Gregory Higby
Numerade Educator
02:42

Problem 11

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=-x^{2}+4, \quad y=3 x+4$

Gregory Higby
Gregory Higby
Numerade Educator
02:42

Problem 12

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=x^{2}-4 x, \quad y=-x+4$

Gregory Higby
Gregory Higby
Numerade Educator
02:55

Problem 13

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=x^{2}-4 x+3, \quad y=-x^{2}+2 x+3$

Lucas Finney
Lucas Finney
Numerade Educator
01:36

Problem 14

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=(x-2)^{2}, \quad y=4-x^{2}$

Lucas Finney
Lucas Finney
Numerade Educator
03:44

Problem 15

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=x, \quad y=x^{3}$

Ahmad Reda
Ahmad Reda
Numerade Educator
01:36

Problem 16

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=x^{2}, \quad y=x^{4}$

Lucas Finney
Lucas Finney
Numerade Educator
02:16

Problem 17

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=\sqrt{x}, \quad y=x^{2}$

Gregory Higby
Gregory Higby
Numerade Educator
01:49

Problem 18

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=x^{3}-6 x^{2}+9 x, \quad y=x^{2}-3 x$

Lucas Finney
Lucas Finney
Numerade Educator
01:55

Problem 19

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=\sqrt{x}, \quad y=-\frac{1}{2} x+1, \quad x=1, \quad x=4$

Linda Hand
Linda Hand
Numerade Educator
02:16

Problem 20

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=2 \sqrt{x}-x, \quad y=-\sqrt{x}$

Gregory Higby
Gregory Higby
Numerade Educator
03:21

Problem 21

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=\frac{1}{x^{2}}, \quad y=x^{2}, \quad x=3$

Gregory Higby
Gregory Higby
Numerade Educator
02:54

Problem 22

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=2 x, \quad y=x \sqrt{x+1}$

Gregory Higby
Gregory Higby
Numerade Educator
08:21

Problem 23

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=-x^{2}+6 x+5, \quad y=x^{2}+5$

Ahmad Reda
Ahmad Reda
Numerade Educator
02:04

Problem 24

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=x \sqrt{4-x^{2}}, \quad y=0$

Linda Hand
Linda Hand
Numerade Educator
02:37

Problem 25

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=\frac{x}{\sqrt{16-x^{2}}}, \quad y=0, \quad x=3$

Lucas Finney
Lucas Finney
Numerade Educator
02:54

Problem 26

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$x=y^{2}+1, \quad x=0, \quad y=-1, \quad y=2$

Gregory Higby
Gregory Higby
Numerade Educator
03:21

Problem 27

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$x=y^{2}, \quad x=y-3, \quad y=-1, \quad y=2$

Gregory Higby
Gregory Higby
Numerade Educator
03:25

Problem 28

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$x=y^{2}, \quad x=2 y+3$

Gregory Higby
Gregory Higby
Numerade Educator
02:42

Problem 29

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=-x^{3}+x, \quad y=x^{4}-1$

Gregory Higby
Gregory Higby
Numerade Educator
01:55

Problem 30

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$\sqrt{x}+\sqrt{y}=1, \quad x+y=1$

Linda Hand
Linda Hand
Numerade Educator
02:16

Problem 31

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=|x|, \quad y=x^{2}-2$

Gregory Higby
Gregory Higby
Numerade Educator
03:49

Problem 32

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=\sin x, \quad y=\frac{2}{\pi} x+1, \quad x=-\frac{\pi}{2}, \quad x=\frac{\pi}{2}$

Leon Druch
Leon Druch
Numerade Educator
01:48

Problem 33

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=\sin 2 x, \quad y=\cos x, \quad x=\frac{\pi}{6}, \quad x=\frac{\pi}{2}$

Lucas Finney
Lucas Finney
Numerade Educator
02:20

Problem 34

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=\cos 2 x, \quad y=\sin x, \quad x=0, \quad x=\frac{3 \pi}{2}$

Ma. Theresa  Alin
Ma. Theresa Alin
Numerade Educator
02:09

Problem 35

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=\sec ^{2} x, \quad y=2, \quad x=-\frac{\pi}{4}, \quad x=\frac{\pi}{4}$

Willis James
Willis James
Numerade Educator
01:51

Problem 36

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=\sec ^{2} x, \quad y=\cos x, \quad x=-\frac{\pi}{3}, \quad x=\frac{\pi}{3}$

Nick Johnson
Nick Johnson
Numerade Educator
02:33

Problem 37

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$y=2 \sin x+\sin 2 x, \quad y=0, \quad x=0, \quad x=\pi$

Ma. Theresa  Alin
Ma. Theresa Alin
Numerade Educator
01:48

Problem 38

Sketch the region bounded by the graphs of the given equations and find the area of that region.
$x=\sin y+\cos 2 y, \quad x=0, \quad y=0, \quad y=\frac{\pi}{2}$

Lucas Finney
Lucas Finney
Numerade Educator
04:50

Problem 39

Find the area of the region in the first quadrant bounded by the parabolas $y=x^{2}$ and $y=\frac{1}{4} x^{2}$ and the line $y=2 .$

Nisha Gautam
Nisha Gautam
Numerade Educator
03:57

Problem 40

Find the area of the region enclosed by the curve $y^{2}=x^{2}\left(1-x^{2}\right)$

Ma. Theresa  Alin
Ma. Theresa Alin
Numerade Educator
06:45

Problem 41

Use integration to find the area of the triangle with the given vertices.
$(0,0),(1,6),(4,2)$

Joy Carpio
Joy Carpio
Numerade Educator
02:05

Problem 42

Use integration to find the area of the triangle with the given vertices.
$(-2,4),(0,-2),(6,2)$

Haricharan Gupta
Haricharan Gupta
Numerade Educator
01:04

Problem 43

Find the area of the region bounded by the given curves (a) using integration with respect to $x$ and
(b) using integration with respect to y.
$y=x^{3}, \quad y=2 x+4, \quad x=0$

Carson Merrill
Carson Merrill
Numerade Educator
02:01

Problem 44

Find the area of the region bounded by the given curves (a) using integration with respect to $x$ and
(b) using integration with respect to y.
$y=\sqrt{x}, \quad y=\frac{1}{2} x, \quad y=1, \quad y=2$

Gregory Cho
Gregory Cho
Numerade Educator
04:40

Problem 45

In the accompanying figure, the function $f$ gives the rate of change of Odyssey Travel's revenue with respect to the amount $x$ it spends on advertising with its current advertising agency. By engaging the services of a different advertising agency, Odyssey expects its revenue to grow at the rate given by the function $g$. Give an interpretation of the area $A$ of the region $S$, and find an expression for $A$ in terms of a definite integral involving $f$ and $g$.

Audrey Fong
Audrey Fong
Numerade Educator
03:27

Problem 46

Two cars start out side by side and travel along a straight road. The velocity of Car $A$ is $f(t) \mathrm{ft} / \mathrm{sec}$, and the velocity of Car $B$ is $g(t)$ ft/sec over the interval $[0, T]$, where $0<T_{1}<T$. Furthermore, suppose that the graphs of $f$ and $g$ are as depicted in the figure. Let $A_{1}$ and $A_{2}$ denote the areas of the regions shown shaded.
a. Write the number
$$
\int_{T_{1}}^{T}[g(t)-f(t)] d t-\int_{0}^{T_{1}}[f(t)-g(t)] d t
$$
in terms of $A_{1}$ and $A_{2}$
b. What does the number obtained in part (a) represent?

Dharmendra Jain
Dharmendra Jain
Numerade Educator
04:04

Problem 47

Use a graphing utility to (a) plot the graphs of the given functions and (b) find the x-coordinates of the points of intersection of the curves. Then find an approximation of the area of the region bounded by the curves using the integration capabilities of the graphing utility.
$y=x^{2}, \quad y=4-x^{4}$

Uma Kumari
Uma Kumari
Numerade Educator
04:03

Problem 48

Use a graphing utility to (a) plot the graphs of the given functions and (b) find the x-coordinates of the points of intersection of the curves. Then find an approximation of the area of the region bounded by the curves using the integration capabilities of the graphing utility.
$y=x^{3}-3 x^{2}+1, \quad y=x^{2}-4$

Uma Kumari
Uma Kumari
Numerade Educator
03:22

Problem 49

Use a graphing utility to (a) plot the graphs of the given functions and (b) find the x-coordinates of the points of intersection of the curves. Then find an approximation of the area of the region bounded by the curves using the integration capabilities of the graphing utility.
$y=x^{3}-4 x^{2}, \quad y=x^{3}-9 x$

Gaurav Kalra
Gaurav Kalra
Numerade Educator
04:04

Problem 50

Use a graphing utility to (a) plot the graphs of the given functions and (b) find the x-coordinates of the points of intersection of the curves. Then find an approximation of the area of the region bounded by the curves using the integration capabilities of the graphing utility.
$y=x^{4}-2 x^{2}+2, \quad y=4-x^{2}$

Uma Kumari
Uma Kumari
Numerade Educator
04:27

Problem 51

Use a graphing utility to (a) plot the graphs of the given functions and (b) find the x-coordinates of the points of intersection of the curves. Then find an approximation of the area of the region bounded by the curves using the integration capabilities of the graphing utility.
$y=x^{2}, \quad y=\sin x$

Steven Clarke
Steven Clarke
Numerade Educator
03:08

Problem 52

Use a graphing utility to (a) plot the graphs of the given functions and (b) find the x-coordinates of the points of intersection of the curves. Then find an approximation of the area of the region bounded by the curves using the integration capabilities of the graphing utility.
$y=\cos x, \quad y=|x|$

Sam Low
Sam Low
Numerade Educator
02:22

Problem 53

In tests conducted by Auto Test Magazine on two identical models of the Phoenix Elite, one equipped with a standard engine and the other with a turbocharger, it was found that the acceleration of the former (in $\mathrm{ft} / \mathrm{sec}^{2}$ ) is given by
$$
a=f(t)=4+0.8 t \quad 0 \leq t \leq 12
$$
$t$ sec after starting from rest at full throttle, whereas the acceleration of the latter (in $\mathrm{ft} / \mathrm{sec}^{2}$ ) is given by
$$
a=g(t)=4+1.2 t+0.03 t^{2} \quad 0 \leq t \leq 12
$$
How much faster is the turbocharged model moving than the model with the standard engine at the end of a $10-\mathrm{sec}$ test run at full throttle?

Dharmendra Jain
Dharmendra Jain
Numerade Educator
03:34

Problem 54

Two dragsters start out side by side. The velocity of Dragster $A, V_{A}$, and the velocity of Dragster $B$, $V_{B}$, for the first 8 sec of the race are shown in the following table, where $V_{A}$ and $V_{B}$ are measured in feet per second. Use Simpson's Rule with $n=8$ to estimate how far Dragster $A$ is ahead of Dragster $B 8 \mathrm{sec}$ after the start of the race.
$$
\begin{array}{|l|l|c|c|c|c|c|c|c|c|}
\hline t \text { (sec) } & 0 & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 \\
\hline V_{A} \text { (ft/sec) } & 0 & 22 & 46 & 70 & 94 & 118 & 142 & 166 & 190 \\
\hline V_{B} \text { (ft/sec) } & 0 & 20 & 44 & 66 & 88 & 112 & 138 & 160 & 182 \\
\hline
\end{array}
$$

Lucas Finney
Lucas Finney
Numerade Educator
02:39

Problem 55

The reservoir located in Central Park in New York City has the shape depicted in the figure below. The measurements shown were taken at 206 -ft intervals. Use Simpson's Rule with $n=10$ to estimate the surface area of the reservoir.

Sheryl Ezze
Sheryl Ezze
Numerade Educator
03:01

Problem 56

A stream is $120 \mathrm{ft}$ wide. The following table gives the depths of the river measured across a section of the river in intervals of $6 \mathrm{ft}$. Here, $\underline{x}$ denotes the distance from one bank of the river, and $y$ denotes the corresponding depth (in feet). The average rate of flow of the river across this section of the river is $4.2 \mathrm{ft} / \mathrm{sec}$. Use Simpson's Rule to estimate the rate of flow of the river.
$$
\begin{array}{l}
\begin{array}{|l|l|l|l|l|l|l|l|l|l|l|l|}
\hline x \text { (ft) } & 0 & 6 & 12 & 18 & 24 & 30 & 36 & 42 & 48 & 54 & 60 \\
\hline y \text { (ft) } & 0.8 & 1.2 & 3.0 & 4.1 & 5.8 & 6.6 & 6.8 & 7.0 & 7.2 & 7.4 & 7.8 \\
\hline
\end{array}\\
\begin{array}{|l|l|l|l|l|l|l|l|l|l|l|}
\hline x \text { (ft) } & 66 & 72 & 78 & 84 & 90 & 96 & 102 & 108 & 114 & 120 \\
\hline y \text { (ft) } & 7.6 & 7.4 & 7.0 & 6.6 & 6.0 & 5.1 & 4.3 & 3.2 & 2.2 & 1.1 \\
\hline
\end{array}
\end{array}
$$

Joseph Liao
Joseph Liao
Numerade Educator
01:39

Problem 57

The weekly total marginal cost incurred by the Advance Visuals Systems Corporation in manufacturing $x$ 19-inch LCD HDTVs is
$$
C^{\prime}(x)=0.000006 x^{2}-0.04 x+120
$$
dollars per set. The weekly marginal revenue realized by the company from the sale of $x$ sets is
$$
R^{\prime}(x)=-0.008 x+200
$$
dollars per set.
a. Plot the graphs of $C^{\prime}$ and $R^{\prime}$ using the viewing window $[0,10,000] \times[0,300] .$
b. Find the area of the region bounded by the graphs of $C^{\prime}$ and $R^{\prime}$ and the vertical lines $x=2000$ and $x=5000$. Interpret your result.

Carson Merrill
Carson Merrill
Numerade Educator
02:35

Problem 58

Find the area of the region bounded by the curve $y^{2}=x^{3}-x^{2}$ and the line $x=2$.

Jacob Fry
Jacob Fry
Numerade Educator
03:51

Problem 59

Find the area of the region bounded by the graph of $f(x)=\sqrt{x}$, the $y$ -axis, and the tangent line to the graph of $f$ at $(1,1) .$

Gregory Higby
Gregory Higby
Numerade Educator
01:47

Problem 60

Find the number $a$ such that the area of the region bounded by the graph of $x=(y-1)^{2}$ and the line $x=a$ is $\frac{9}{2}$.

Narayan Hari
Narayan Hari
Numerade Educator
04:01

Problem 61

Find the area of the region bounded by the $x$ -axis and the graph of $f(x)=x^{4}-2 x^{3}$ and to the right of the vertical line that passes through the point at which $f$ attains its absolute minimum.

Anurag Kumar
Anurag Kumar
Numerade Educator
01:06

Problem 62

The area of the region in the right half plane bounded by the $y$ -axis, the parabola $y=-x^{2}-2 x+3$, and a line tangent to the parabola is $\frac{x}{3}$. Find the coordinates of the point of tangency.

Fuzail Shakir
Fuzail Shakir
Numerade Educator
10:20

Problem 63

The region $S$ is bounded by the graphs of $y=\sqrt{x}$, the $x$ -axis, and the line $x=4$.
a. Find $a$ such that the line $x=a$ divides $S$ into two subregions of equal area.
b. Find $b$ such that the line $y=b$ divides $S$ into two subregions of equal area.

Robert Leedy
Robert Leedy
Numerade Educator
19:56

Problem 64

Find the value of $c$ such that the parabola $y=c x^{2}$ divides the region bounded by the parabola $y=\frac{1}{4} x^{2}$, and the lines $y=2$, and $x=0$ into two subregions of equal area.

Leon Druch
Leon Druch
Numerade Educator
02:04

Problem 65

Let $A(x)$ denote the area of the region in the first quadrant completely enclosed by the graphs of $f(x)=x^{m}$ and $g(x)=x^{1 / m}$, where $m$ is a positive integer.
a. Find an expression for $\overline{A(m) \text { . }}$
b. Evaluate $\lim _{m \rightarrow 1} A(m)$ and $\lim _{m \rightarrow \infty} A(m) .$ Give a geomet-
ric interpretation.
c. Verify your observations in part (b) by plotting the graphs of $f$ and $g$.

Vikash Ranjan
Vikash Ranjan
Numerade Educator
04:50

Problem 66

Let $f(x)=\frac{1}{x^{2}+1}$ and $g(x)=|x|$.
a. Plot the graphs of $f$ and $g$ using the viewing window $[-1,1] \times[0,1.5] .$ Find the points of intersection of the graphs of $f$ and $g$ accurate to three decimal places.
b. Use a calculator or computer and the result of part (a) to find the area of the region bounded by the graphs of $f$ and $q$.

Harmender Singh Yadav
Harmender Singh Yadav
Numerade Educator
01:22

Problem 67

The curve with equation $y^{2}-4 x^{3}+4 x^{4}=0$ is called a piriform.
a. Plot the curve using the viewing window $[-1,1] \times[-1,1]$
b. Find the area of the region enclosed by the curve accurate to five decimal places.

Kenneth Kobos
Kenneth Kobos
Numerade Educator
03:10

Problem 68

The curve with equation $4 y^{2}-4 x y^{2}-x^{2}-x^{3}=0$ is called a right strophoid.
a. Plot the curve using the viewing window $[-1.5,1.5] \times[-0.5,0.5]$
b. Find the area of the region enclosed by the loop of the curve.

Bailey Brooks
Bailey Brooks
Numerade Educator
01:57

Problem 69

Determine whether the statement is true or
false. If it is true, explain why it is true. If it is false, explain why or give an example to show why it is false.
If $A$ denotes the area bounded by the graphs of $f$ and $g$ on $[a, b]$, then
$$
A^{2}=\int_{a}^{b}[f(x)-g(x)]^{2} d x
$$

Dharmendra Jain
Dharmendra Jain
Numerade Educator
01:50

Problem 70

Determine whether the statement is true or
false. If it is true, explain why it is true. If it is false, explain why or give an example to show why it is false.
If $f$ and $g$ are continuous on $[a, b]$ and $\int_{a}^{b}[f(t)-g(t)] d t>0$, then $f(t) \geq g(t)$ for all $t$ in $[a, b]$.

Dharmendra Jain
Dharmendra Jain
Numerade Educator
10:14

Problem 71

Determine whether the statement is true or
false. If it is true, explain why it is true. If it is false, explain why or give an example to show why it is false.
Two cars start out traveling side by side along a straight road at $t=0$. Twenty seconds later, $\operatorname{Car} A$ is $30 \mathrm{ft}$ behind Car $B$. If $v_{1}$ and $v_{2}$ are continuous velocity functions for Car $A$ and Car $B$, respectively, where $v_{1}(t)$ and $v_{2}(t)$ are measured in feet per second, then
$$
\int_{0}^{20} v_{2}(t) d t=\int_{0}^{20} v_{1}(t) d t+30
$$

Ernest Castorena
Ernest Castorena
Numerade Educator
00:55

Problem 72

Determine whether the statement is true or
false. If it is true, explain why it is true. If it is false, explain why or give an example to show why it is false.
Suppose that the acceleration of $\operatorname{Car} A$ and Car $B$ along a straight road are $a_{1}(t) \mathrm{ft} / \mathrm{sec}^{2}$ and $a_{2}(t) \mathrm{ft} / \mathrm{sec}^{2}$, respectively, over the time interval $\left[t_{1}, t_{2}\right]$, where $a_{1}$ and $a_{2}$ are continuous functions with $a_{1}(t) \geq a_{2}(t)$ on $\left[t_{1}, t_{2}\right]$. Then at time $t=t_{2}$, Car $A$ will be traveling $\int_{n}^{\int_{2}}\left[a_{1}(t)-a_{2}(t)\right] d t \mathrm{ft} / \mathrm{sec}$ faster than Car $B$. (Assume that $t$ is measured in seconds.)

Stephen Hobbs
Stephen Hobbs
Numerade Educator