Math 2401: Differential Equations

Page Status: Current, Fall 2009
Last Update: Tuesday, November 10, 2009
Page Author & Instructor: Barry McQuarrie


Session: Fall 2009        Instructor: Barry McQuarrie        Office Hours:
MWF 8:00-9:05am Office: Science 1380 MWF 9:15-10:30am
Location: Sci 1030 Phone: 589-6302 (I do not use voicemail) Th 10:30-11:30am
mcquarrb@morris.umn.edu drop in (if my door is open we can talk, if it is closed I am not available)
http://cda.morris.umn.edu/~mcquarrb/ other times via email appointment


Course Prerequisites

To succeed in this course you will need to have mastered basic calculus (Calculus I and II). Although the only prerequisite to the course is calculus, we will be using ideas from linear algebra and complex-valued functions extensively. The underlying theory of differential equations has a deep connection with linear algebra, and I will be pointing out these connections as we proceed. We will develop the concepts we need from other areas of mathematics in class or on assignments.

Most students in the class will have some experience with the computer algebra system Mathematica in Calculus I and II. If you have never used Mathematica before, do not despair! I will be using it occasionally in class, and will provide you with resources to help you use Mathematica when you need it on Assignments. Mathematica will never do our thinking for us. It will help us understand concepts and answer questions that would be difficult to answer if we were working the solution out solely by hand. The vast majority of the work in this class will be done using our brains, pencils, and paper!

Goals

A student taking this course should expect to be able to

Beyond the curriculum, you should also expect to

Textbook

NOTE: TEXTBOOK EDITION IS ACCURATE FOR Fall 2009.

Boyce and DiPrima Elementary Differential Equations and Boundary Value Problems 9th, 8th, or the 7th Ed--the bookstore will have the latest edition, and the course calendar below is based on the 9th Edition. The differences between the editions is minimal, but if you use an earlier edition be aware that some of the sections may be numbered differently, content may be slightly different, and problems listed as practice below may not line up with your older edition.

Another text that presents the concepts with more readability (but lacking the depth of Boyce and DiPrima) is Zill A First Course in Differential Equations with Modeling Applications. If you are looking for a secondary reference this would be an excellent choice. This is NOT the primary text for the course, it is optional.

Time Commitment

University policy says ``one credit is defined as equivalent to an average of three hours of learning effort per week (over a full semester) necessary for an average student to achieve an average grade in the course''. Our course is a four-credit course, meeting approximately three hours per week: 4 credits times 3 hours/week/credit - 3 hours/week in lecture = 9 hours/week outside class. Thus, you are expected to spend 9 hours per week working outside of class, reading the textbook and working problems.

Please make the most of my office hours! The content of the course can be difficult at times and I expect to see you all in my office at some time or other. To get the most out of the course you should

Course Components

Practice. Practice questions will not be collected. Solutions to the practice problems are available on the course web page. The purpose of the practice problems is to focus your attention on the important lessons of the day, to serve as a starting point for solving the assignments, to serve as a guide to what I consider a complete solution to problems, and to serve as review for tests. You should do as much extra homework as you deem necessary to enhance your understanding of a topic. I can not stress enough how important it is that you work problems! The practice problems identify the types of problems from the text that should be mastered. Although these practice problems will not be graded, I believe you will have a hard time succeeding in the course unless you spend the time to understand them. Falling behind in this course, as in any university course, can lead to disaster, so it is important that you keep up with the homework.

WeBWorK. (58 questions total) You will be completing some of your assignments using the online homework utility WeBWorK, which you can learn more about here. The WeBWorK problems are provided to give you practice implementing the computational techniques we will be studying, although occasionally a problem will be more theoretical in nature. There are seven WeBWorK problem sets for the course, five due at the midterm and two due before the final exam. I have provided links to the WeBWorK problem sets in the course calender below.

Assignments. (about 20 questions total) Assignments will be handed out well in advance of the due date. Assignments I have handed out to the class will be available outside my office. The assignments will take some time to complete, and it is important that you begin work on them immediately. Assignments will be handed in during class on the day they are due, unless you have spoken to me beforehand and I have granted an extension. Putting assignments in my mailbox or under my office door while I am teaching another course is severely frowned upon unless we have agreed that you will be doing this. If this is done when I am teaching your class I will not accept the work--believe it or not, people have actually done this!

Assignment solutions should be a self-contained document. They should be written legibly, contain diagrams or tables where appropriate, and should state the problem and clearly explain the solution. If you have used a significant amount of Mathematica in your solution, please print out the Mathematica notebook and include it as part of your solution.

Midterm Exam. The midterm will consist of five problems--possibly some short answer or true/false questions, along with questions dealing with the application of the techniques we have learned. You will not be allowed any outside material on your desks during the midterm exam (calculators will be allowed, but should not be necessary to solve the problems). The exam should not be significantly harder than the assignments; my tests tend to be long, so do not be alarmed if you require the entire class time to complete the test. There will be no Mathematica component to the exam.

Final Exam. The final exam will be similar in format to the midterm exam, except slightly longer, and cover only the material since the midterm exam.

Grading

Here is the University-wide uniform grading policy.

A few of you may be taking the course S-N. In this case, you need to earn a C- to receive an S.

The grade for the course will be calculated by the following formula:

WeBWorK 35%
Assignments 25%
Midterm Exam 20%
Final Exam 20%

Your numerical grades will be converted to letter grades and finally Grade Points via the following cutoffs (see the UMM Catalog for more on Grades and Grading Policy):

Numerical 95% 90% 87% 83% 80% 77% 73% 70% 65% 60% Below 60%
Letter A A- B+ B B- C+ C C- D+ D F
Grade Point 4.00 3.67 3.33 3.00 2.67 2.33 2.00 1.67 1.33 1.00 0.00

Please note that you are not competing against your fellow students. I will adjust the difficulty of the questions and the severity of the grading so that, for example, a B+ score corresponds to what I consider B+ achievement.

Respectful Classroom

Further Course Information and Resources

Mathematica Resources

At UMM the computer algebra system of choice is Mathematica (I typically abbreviate this as MMA), and I use it extensively in most of the courses I teach. FYI, files ending in .nb are Mathematica files.

Mathematica is expensive, and we do not expect our students to purchase it. UMM has a site licence for Mathematica, and it can be found on any computer on campus (PC or MacIntosh). When you need to work with Mathematica outside of class, visit one of the many computer labs on campus.

If you have specific questions about Mathematica while working on homework, bring the file you are working with to office hours on a usb drive and we can look at it together, or email the file to yourself (or me) before you come to office hours. Most questions can be answered in under 10 minutes.


Course Calendar

# Date Assignment Lecture Topic Practice Resources
 
Aug 24    
1 Aug 26 ww: Preliminaries Course Introduction & Review Read: How to Succeed in My Courses MMA (review DE as seen in calculus)
2 Aug 28   1.1 1.2 1.3 Terminology 1.3: 1-7,14 Read 1.4 MMA (used in lecture)
 
  Aug 31 ww: Direction Fields 2.1 Linear Equations 2.1: 7,18,28 | 2.1.nb Homework 2.1.7 has an excellent MMA example, including plotting families of curves and direction fields.
3 Sep 2 2.2 Separable Equations
2.3 Modeling
2.2: 1,4,24 | 2.2.nb MMA (Mixing Problem)
4 Sep 4 ww: Separable 2.4 Differences Between Linear & Nonlinear Equations 2.4: 15,20,21 | 2.4.nb MMA (used in lecture)
 
5 Sep 7   Labour Day--no class    
6 Sep 9   2.5 Autonomous Equations and Population Dynamics 2.5: 1,3,8 Lecture: notes | MMA (autonomous equations)
7 Sep 11 ww: First Order Linear & Exact 2.6 Exact Equations and Integrating Factors 2.6: 1,16 | 2.6.nb  
 
8 Sep 14 Taylor Method of Order n: Numerical Solutions to IVP Read 2.7 Numerical Solutions
9 Sep 16 2.8 The Existence & Uniqueness Theorem
Concept Map
2.8: 1,7,14 | 2.8.nb MMA (Picard's iteration method)
10 Sep 18 3.1 Homogeneous Equations Constant Coefficients 3.1: 1,5,7,9 | 3.1.nb
2.9: 36,42 | 2.9.nb
MMA (used in lecture)
 
11 Sep 21 3.2 Solutions of Linear Homogeneous & Wronskian 3.2: 1,6,9 | 3.2.nb Handout (includes flowchart of theorems)
12 Sep 23 3.3 Complex Roots of Characteristic Equation 3.3: 1,3,7,17  
13 Sep 25 3.4 Repeated Roots & Reduction of Order 3.4: 6,7,11,16,20,23 | 3.4.nb MMA (repeated, complex, distinct roots)
 
14 Sept 28 3.5 Nonhomogeneous: Undetermined Coefficients 3.5: 3,7,17 | 3.5.nb
15 Sep 30 Assignment #1 Due 3.5 Nonhomogeneous: Undetermined Coefficients lecture | MMA (associated with Handout)
16 Oct 2 3.6 Variation of Parameters 3.6: 1,4,13 | 3.6.nb  
 
17 Oct 5   3.7 Application: Vibrations 3.7: 1,6,11 | 3.7.nb MMA (Three Types of Damping)
18 Oct 7   3.8 Application: Forced Vibrations
Meet in Imholte 11 Computer Lab
MMA (Numerical solutions)
19 Oct 9 ww: Higher Order Linear 4.1 General Theory
4.2 Homogeneous Equations Constant Coefficients
4.1: 4,6,7,11
4.2: 1,3,4,8,11,13,18 | 4.2.nb
MMA (repeated roots)
Roots of Unity
 
20 Oct 12 4.3 Undetermined Coefficients
4.4 Variation of Parameters
4.3: 1,4 4.4: 1,3 | 4.3.nb Lecture: notes | MMA
21 Oct 14   Chapter 1, 2, 3 & 4 Review   Review Notes | Previous Test Questions | Concept Map
22 Oct 16 Midterm Exam on Chapters 1, 2, 3 & 4
 
  Oct 19   Fall Break--no class    
23 Oct 21 Assignment #2 Due 5.1 Power Series Review 5.1: 1,8,15,16,21,25 | 5.1.nb MMA (series review)
24 Oct 23   5.2 & 5.3 Series Solution about Ordinary Point
Concept Map
5.2: 1,2,21 | 5.2.nb MMA (related to lecture)
The homework has an in-depth discussion of Hermite Polynomials (5.2.21)
 
25 Oct 26   5.2 & 5.3 Series Solution about Ordinary Point 5.3: 5,7,11 | 5.3.nb MMA (further explorations of the problem solved by hand in class)
26 Oct 28 5.4 Euler Equations & Regular Singular Points 5.4: 1,2,9,17,20,21,41 MMA (series solution: series products, what's special about singular points)
27 Oct 30 5.5 & 5.6 Series Solutions about Regular Singular Point 5.5: 1, 3
5.6: 1, 11
 
28 Nov 2 Series Solutions in General (not looking for patterns) Lecture: notes | MMA | Notes from 1986
29 Nov 4 5.7 Bessel's Equation Lecture: notes | MMA &
Physics Today Article: Special Functions
30 Nov 6 ww: Laplace Transforms 6.1 Definition of Laplace Transform
6.2 Solution of Initial Value Problems
6.1: 2, 5, 6, 17 | 6.1.nb
6.2: 5, 10, 27 | 6.2.nb
MMA (basics for Laplace transform)
 
31 Nov 9   6.3 Step Functions 6.3: 4, 7, 18 | 6.3.nb MMA (basics for step functions)
32 Nov 11 6.4 DEs with Discontinuous Forcing Functions 6.4: 3, 11, 19 | 6.4.nb  
33 Nov 13 Assignment #3 Due 6.5 Impulse Functions 6.5: 5, 14 | 6.5.nb MMA (basics for impulse functions)
FYI: Generalized Functions
 
34 Nov 16 7.1 Introduction 7.1: 1,4,6,8 | 7.1.nb
Read 7.2
 
35 Nov 18 ww: Systems 7.3 Systems of Algebraic Equations 7.3: 15,18,21 | 7.3.nb MMA (eigensystems)
  Nov 20 7.3 Systems of Algebraic Equations
7.4 Basic Theory
7.4: 4 Pronunciation of the Greek Alphabet
 
36 Nov 23 7.5 Homogeneous Linear Systems Constant Coefficients 7.5: 16 MMA (eigensystems in Mathematica)
37 Nov 25 7.6 Complex Eigenvalues
7.8 Repeated Eigenvalues
7.6: 9
7.8: 9,13
 
38 Nov 27   Thanksgiving Holiday--No Class    
 
39 Nov 30   7.9 Nonhomogeneous Systems 7.9: 1  
40 Dec 2 9.1 The Phase Plane: Linear Systems 9.1: 1 MMA (phase plane and stability)
41 Dec 4 9.2 Autonomous Systems and Stability Numerical Solutions
 
42 Dec 7 9.3 Locally Linear Systems
43 Dec 9 9.4 Competing Species
44 Dec 11 Assignment #4 Due Chapter 5, 6, 7 & 9 Review Review Notes | Practice Test Questions
 
  Tues Dec 15 8:30-10:30am Final Exam on Chapter 5,6,7, and bits of 9