chapter 9 differential equations - abbymath.comabbymath.com/classes/calculusc/chapter9.pdf ·...

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Chapter 9 Differential Equations 9-2 Direction Fields and Euler’s Method 9-3 Separable Equations 3-8 Exponential Growth and Decay 9-4 The Logistic Equation 9-5 First-Order Linear Differential Equations The following notes are for the Calculus C (SDSU Math 151) classes I teach at Torrey Pines High School. I wrote and modified these notes over several semesters. The explanations are my own; however, I borrowed several examples and diagrams from the textbooks* my classes used while I taught the course. Over time, I have changed some examples and have forgotten which ones came from which sources. Also, I have chosen to keep the notes in my own handwriting rather than type to maintain their informality and to avoid the tedious task of typing so many formulas, equations, and diagrams. These notes are free for use by my current and former students. If other calculus students and teachers find these notes useful, I would be happy to know that my work was helpful. - Abby Brown * , 6th & 4th editions, James Stewart, ©2007 & 1999 Brooks/Cole Publishing Company, ISBN 0-495-01166-5 & 0-534-36298-2. (Chapter, section, page, and formula numbers refer to the 6th edition of this text.) , 5th edition, Roland E. Larson, Robert P. Hostetler, & Bruce H. Edwards, Calculus: Early Transcendentals *Calculus ©1994 D. C. Heath and Company, ISBN 0-669-35335-3. SDUHSD Abby Brown Calculus II/C SDSU Math 151 www.abbymath.com San Diego, CA Note: You will need a calculator for most of these notes. On a test, the numbers will be nice enough that you won’t need a calculator. Name: ___________________________________ www.abbymath.com - Ch. 9 Page 1 of 14

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Page 1: Chapter 9 Differential Equations - abbymath.comabbymath.com/Classes/CalculusC/Chapter9.pdf · Chapter 9 Differential Equations 9-2 Direction Fields and Euler’s Method 9-3 Separable

Chapter 9Differential Equations

9-2 Direction Fields and Euler’s Method9-3 Separable Equations3-8 Exponential Growth and Decay9-4 The Logistic Equation9-5 First-Order Linear Differential Equations

The following notes are for the Calculus C (SDSU Math 151)classes I teach at Torrey Pines High School. I wrote andmodified these notes over several semesters. Theexplanations are my own; however, I borrowed severalexamples and diagrams from the textbooks* my classes usedwhile I taught the course. Over time, I have changed someexamples and have forgotten which ones came from whichsources. Also, I have chosen to keep the notes in my ownhandwriting rather than type to maintain their informalityand to avoid the tedious task of typing so many formulas,equations, and diagrams. These notes are free for use by mycurrent and former students. If other calculus students andteachers find these notes useful, I would be happy to knowthat my work was helpful. - Abby Brown

* , 6th & 4th editions, James Stewart, ©2007 & 1999Brooks/Cole Publishing Company, ISBN 0-495-01166-5 & 0-534-36298-2.(Chapter, section, page, and formula numbers refer to the 6th edition of this text.)

, 5th edition, Roland E. Larson, Robert P. Hostetler, & Bruce H. Edwards,

Calculus: Early Transcendentals

*Calculus ©1994D. C. Heath and Company, ISBN 0-669-35335-3.

SDUHSD

Abby Brown

Calculus II/CSDSU Math 151

www.abbymath.comSan Diego, CA

Note: You will need a calculator for most of thesenotes. On a test, the numbers will be nice enoughthat you won’t need a calculator.

Name: ___________________________________ www.abbymath.com - Ch. 9

Page 1 of 14

Page 2: Chapter 9 Differential Equations - abbymath.comabbymath.com/Classes/CalculusC/Chapter9.pdf · Chapter 9 Differential Equations 9-2 Direction Fields and Euler’s Method 9-3 Separable

2 1 1 2x

2

1

1

2

y

4 3 2 1 1 2 3 4x

4

3

2

1

1

2

3

4

y

Name: ___________________________________ www.abbymath.com - Ch. 9

Page 2 of 14

Page 3: Chapter 9 Differential Equations - abbymath.comabbymath.com/Classes/CalculusC/Chapter9.pdf · Chapter 9 Differential Equations 9-2 Direction Fields and Euler’s Method 9-3 Separable

4 3 2 1 1 2 3 4x

1

1

2

3

4

5

6

7

8

y

4 3 2 1 1 2 3 4x

1

2

3

4

y

Name: ___________________________________ www.abbymath.com - Ch. 9

Page 3 of 14

Page 4: Chapter 9 Differential Equations - abbymath.comabbymath.com/Classes/CalculusC/Chapter9.pdf · Chapter 9 Differential Equations 9-2 Direction Fields and Euler’s Method 9-3 Separable

Name: ___________________________________ www.abbymath.com - Ch. 9

Page 4 of 14

Page 5: Chapter 9 Differential Equations - abbymath.comabbymath.com/Classes/CalculusC/Chapter9.pdf · Chapter 9 Differential Equations 9-2 Direction Fields and Euler’s Method 9-3 Separable

0.2 0.4 0.6 0.8 1.0 1.2 1.4x

1.0

1.5

2.0

2.5

3.0

3.5y

h 1

h 0.5

h 0.25h 0.2

h 0.1

h 0.05h 0.02

Step Size Euler Estimate y 3

1.000 1.50000

0.500 1.28333

0.400 1.24360

0.200 1.16823

0.100 1.13269

0.050 1.11546

0.010 1.10195

0.005 1.10028

0.001 1.09895

n x y

0 1.0 0.00000

1 1.1 0.10000

2 1.2 0.19091

3 1.3 0.27424

4 1.4 0.35117

5 1.5 0.42259

6 1.6 0.48926

7 1.7 0.55176

8 1.8 0.61058

9 1.9 0.66614

10 2.0 0.71877

11 2.1 0.76877

12 2.2 0.81639

13 2.3 0.86184

14 2.4 0.90532

15 2.5 0.94699

16 2.6 0.98699

17 2.7 1.02545

18 2.8 1.06249

19 2.9 1.09820

20 3.0 1.13269

Step Size Euler Estimate y 1

1.000 2.0000000

0.500 2.5000000

0.250 2.8828125

0.200 2.9766400

0.100 3.1874849

0.050 3.3065954

0.020 3.3831761

0.010 3.4096277

0.005 3.4230342

0.001 3.4338479

3 2 1 1 2 3x

3

2

1

1

2

y

1 2 3 4x

1.0

0.5

0.5

1.0

1.5

y

e

Name: ___________________________________ www.abbymath.com - Ch. 9

Page 5 of 14

Page 6: Chapter 9 Differential Equations - abbymath.comabbymath.com/Classes/CalculusC/Chapter9.pdf · Chapter 9 Differential Equations 9-2 Direction Fields and Euler’s Method 9-3 Separable

Name: ___________________________________ www.abbymath.com - Ch. 9

Page 6 of 14

Page 7: Chapter 9 Differential Equations - abbymath.comabbymath.com/Classes/CalculusC/Chapter9.pdf · Chapter 9 Differential Equations 9-2 Direction Fields and Euler’s Method 9-3 Separable

4 2 2 4

4

2

2

4 2 2 4

4

2

2

Name: ___________________________________ www.abbymath.com - Ch. 9

Page 7 of 14

Page 8: Chapter 9 Differential Equations - abbymath.comabbymath.com/Classes/CalculusC/Chapter9.pdf · Chapter 9 Differential Equations 9-2 Direction Fields and Euler’s Method 9-3 Separable

4 2 2x

4

2

2

y

Name: ___________________________________ www.abbymath.com - Ch. 9

Page 8 of 14

Page 9: Chapter 9 Differential Equations - abbymath.comabbymath.com/Classes/CalculusC/Chapter9.pdf · Chapter 9 Differential Equations 9-2 Direction Fields and Euler’s Method 9-3 Separable

4 2 2 4

4

2

2

4

4 2 2 4

4

2

2

4

4 2 2 4

4

2

2

4

4 2 2 4

4

2

2

4

Name: ___________________________________ www.abbymath.com - Ch. 9

Page 9 of 14

Page 10: Chapter 9 Differential Equations - abbymath.comabbymath.com/Classes/CalculusC/Chapter9.pdf · Chapter 9 Differential Equations 9-2 Direction Fields and Euler’s Method 9-3 Separable

1 2 3 40.5 1.5 2.5 3.5Day

50

100

150

200

250

300

25

75

125

175

225

275

P

Name: ___________________________________ www.abbymath.com - Ch. 9

Page 10 of 14

Page 11: Chapter 9 Differential Equations - abbymath.comabbymath.com/Classes/CalculusC/Chapter9.pdf · Chapter 9 Differential Equations 9-2 Direction Fields and Euler’s Method 9-3 Separable

10 20 30 40 50 60 70 80 90 100t

100200300400500600700800900

100011001200

P

10 20 30 40 50 60 70 80 90 100t

100200300400500600700800900

100011001200

P

Name: ___________________________________ www.abbymath.com - Ch. 9

Page 11 of 14

Page 12: Chapter 9 Differential Equations - abbymath.comabbymath.com/Classes/CalculusC/Chapter9.pdf · Chapter 9 Differential Equations 9-2 Direction Fields and Euler’s Method 9-3 Separable

20 40 60 80t

200

400

600

800

1000

P

h 20h 10

h 1

Step Size Euler Estimate P 40 Euler Estimate P 80

20 539 1032

10 647 997

5 695 991

1 725 986

0.1 731 985

Name: ___________________________________ www.abbymath.com - Ch. 9

Page 12 of 14

Page 13: Chapter 9 Differential Equations - abbymath.comabbymath.com/Classes/CalculusC/Chapter9.pdf · Chapter 9 Differential Equations 9-2 Direction Fields and Euler’s Method 9-3 Separable

Name: ___________________________________ www.abbymath.com - Ch. 9

Page 13 of 14

Page 14: Chapter 9 Differential Equations - abbymath.comabbymath.com/Classes/CalculusC/Chapter9.pdf · Chapter 9 Differential Equations 9-2 Direction Fields and Euler’s Method 9-3 Separable

Name: ___________________________________ www.abbymath.com - Ch. 9

Page 14 of 14