Rouben Rostamian

MATH 225: Introduction to Differential Equations

Fall 2024 Course information

Class Time/Place:    MoWe 2:30pm–3:45pm, BIOL 120
Office: Math/Psych 402
Phone: 410–455–2458
Email: rostamian@umbc.edu
Office hours: MoWe 4:00–5:30, or by appointment

Textbook and course content

Textbook: Stanley J. Farlow, An Introduction to Differential Equations and their Applications, available at the UMBC Bookstore, Amazon, and elsewhere.

This excellent and very affordable paperback book is a black-and-white reproduction of the original 1994 color hardcover edition which is no longer in print. There has been only a single edition of this book, and as is a common occurrence with first editions, it suffers from more than the expected number of typos/errors. I maintain an errata website where readers from all over the country report errors that they spot in the book. If you spot an unreported error, be sure to let me know and I will add you to that website with due acknowledgment.

Beware! The electronic version of the book brings in a large number of additional errors due to poor optical scanning. Stay away from the e-book if possible.

We will cover much of

Chapter 1:
Introduction to differential equations
Chapter 2:
First-order differential equations
Chapter 3:
Second-order differential equations
Chapter 5:
The Laplace transform
Chapter 6:
Systems of differential equations

Calculus II (Math 152) is a prerequisite. A knowledge of Multivariable Calculus (Math 251) and Linear Algebra (Math 221) will give you an edge but is not a prerequisite; I will fill in the missing details as needed.

Course Goals/Objectives

The subject of this is course is an introduction to ordinary differential equations and their applications. It's pretty much a natural continuation of calculus, so if you liked calculus, you will like this course. In this course you will learn:

Weekly homework and quizzes

I will put homework assignments on this web page shortly after each class. I will not collect homework but I expect that you do your best to solve them all. There will be a 10-minute quiz at the beginning of the class every Wednesday (except for the first week of classes and the weeks of Exams 1 and 2). The quiz questions will be slight variations of some of the homework exercises assigned on the Monday and Wednesday of the previous week. I will return the graded quizzes to you on the following Monday.

There won't be make-up quizzes; please don't ask for exceptions. However the two lowest quiz grades will be dropped to accommodate unanticipated or conflicting events.

Exams and grading

Exams 1 and 2 will cover approximately the first third and second third of the course; they will be given in the regularly scheduled class times.

The Final Exam will be comprehensive—it will cover the entire course—however it will put much greater emphasis on the material toward the later parts of the course. on the material of Oct 28 through the semester's end.

Quizzes: 20%
Exam 1: 25%
Exam 2: 25%
Final Exam: 30%

Your course grade will be calculated according to the weights attached to various components as shown in the adjacent table. Letter grades will be determined according to:

if { grade ≥ 85: A}
else if { grade ≥ 75: B}
else if { grade ≥ 65: C}
else if { grade ≥ 55: D}
else F

I will make and grade the exams in a fair and reasonable way, but sorry, no "curving" in this course.

Homework assignments

Homework assignments
Aug 28 Sec 1.1: #1–10, 18
Sec 2.1: #2, 4, 5, 6, 9
Sep 2 Labor Day – no class today
Sep 4 Sec 2.1: # 16, 17, 18, 25, 26
Sec 2.2: #12, 13, 17, 18, 23, 26, 28
Sep 9 Sec 2.3: #7, 8, 10, 14
Sep 11 Sec 2.4: #1, 3, 4, 5, 6, 7
Sep 16 Sec 2.5: #5, 7, 8, 9, 12
Sep 18 Sec 2.6: #12, 13, 16, 17
Sep 23 Sec 2.7: #19, 20, 27
Optional (for programming fans): Sec 2.7: #21–25
Sep 25 Sec 3.1: #1–13, 25, 27, 28
Sep 30 Sec 3.3: #6, 7, 8, 9, 18, 19, 20
Oct 2 Exam #1 based on the material of Aug 28 through Sep 23
Oct 7 Sec 3.4: #4, 5, 6, 21, 22
Oct 9 Sec 3.4: #8, 9, 12, 13, 14, 16, 17, 18
Oct 14 Sec 3.5: #1, 12–15
Oct 16 Sec 3.7: #6, 7, 10, 11, 14, 15
Oct 21 Sec 3.7: #17, 18, 23, 25, 26, 29, 30, 31, 35
Oct 23 No additional homework assigned today
Oct 28 Sec 3.8: #8, 9, 10, 14, 15
Oct 30 Exam #2 based on the material of Sep 25 through Oct 23
Nov 4 Sec 3.9: #6–9
Nov 6 Sec 3.10: #12, 13, 14, 16
Nov 11 Sec 3.11: #1, 6, 7, 8
Additionally: How is equation (9) in Sec 3.11 obtained?
Nov 13 Sec 5.1: #1, 5, 9, 10, 12
Nov 18 Sec 5.2: #4, 6, 8, 11, 17
Nov 20 Sec 5.3: #5–10, 12, 13
Sec 5.4: #8–12, 14
Nov 25 Sec 5.5: #1, 5, 7, 8, 9, 10, 12, 15, 16, 18
Nov 27 Sec 5.6: #4, 6, 7, 9, 11, 12
Dec 2 Sec 5.7: #7, 8, 9, 11, 13
Dec 4 Exercises 1–4 in this PDF
Dec 9 Final remarks
Final Exam: Friday Decemer 13, 1:00–3:00pm
based on the material of Oct 28 to end

Notes & Comments

Registrar's info
Registrar's Office Dates and Deadlines

Errata
Reported mathematical and typographical error in the printed version of the textbook

Particular solutions
The approach outlined in particular-solution-flowchart.pdf offers an alternative to Table  on Farlow's page 153.

Solutions to quizzes and exams
Quiz #1:  Solutions    Grade distribution
Quiz #2 solution
Quiz #3 solution
Exam #1:  Solutions    Grade distribution
Quiz #4 solution
Quiz #5 solution
Quiz #6 solution
Exam #2:  Solutions    Grade distribution
Quiz #7 solution
Quiz #8 solution
Quiz #9 solution
Quiz #10 solution
Quiz #11 solution
Final exam:  Solutions    Grade distribution

Laplace transform formulas
These formulas are all you need to solve all your Laplace Transform problems. You will get a copy of this on your final exam.

Course grade calculator
Try this utility to estimate or calculate your course grade.

 

Tutoring available

Tutoring service is available for this course. Go to Math and Science Tutoring Center for more information.

Student Disability Services (SDS)

Services for students with disabilities are provided for all students qualified under the Americans with Disabilities Act of 1990, the ADAA of 2009, and Section 504 of the Rehabilitation Act who request and are eligible for accommodations. The Office of Student Disability Services is the UMBC department designated to coordinate accommodations that would allow for students to have equal access and inclusion in their courses.

UMBC Honors Code

By enrolling in this course, each student assumes the responsibilities of an active participant in UMBC's scholarly community in which everyone's academic work and behavior are held to the highest standards of honesty. Cheating, fabrication, plagiarism, and helping others to commit these acts are all forms of academic dishonesty, and they are wrong. Academic misconduct could result in disciplinary action that may include, but is not limited to, suspension or dismissal.

The PDF document UMBC Policy for Undergraduate Student Academic Conduct spells out the official academic integrity policies for undergraduates.