Homework Assignments
MAP 2302, Sections 3226 & 5010 -- Elementary Differential Equations
Fall 2003


Last update made by D. Groisser Sun Dec 14 17:36:11 EST 2003

Homework problems and due dates (not the dates the problems are assigned) are listed below. This list, especially the due dates, will be updated frequently, usually in the late afternoon or evening the day of class or the next morning. Due dates and assignments more than one lecture ahead are estimates; in particular, due dates may be moved either forward or back, and problems not currently on the list from a given may be added later (but prior to their due dates, of course). On a given day there may be problems due from more than one section of the book.

Exam dates and some miscellaneous items may also appear below.

If one day's assignment seems lighter than average, it's a good idea to read ahead and start doing the next assignment, which may be longer than average.

Unless otherwise indicated, problems are from our textbook (Nagle, Saff, & Snider, 4th edition). It is intentional that some of the problems assigned do not have answers in the back of the book or solutions in a manual. An important part of learning mathematics is learning how to figure out by yourself whether your answers are correct.

Read the corresponding section of the book before working the problems. Don't just read the examples, and don't just try the homework problems and refer to the text only if you get stuck.

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Date due Section # / problem #'s
W 8/27/03
Read the syllabus and the web handout "Taking notes in a college math class"

Do problems 1.1/ 1-16. Also, do non-book problem #1. Note: if you have a problem viewing any of my PDF files, check your version of Adobe Acrobat at http://www.adobe.com/products/acrobat/ . You may need to update.


F 8/29/03
1.2/ 1-5, 10, 11, 14, 15, 19. Also, read the handout "What is a solution?", obtainable from the Web.Also, do non-book problem #2.
W 9/3/03
1.2/ 18, 23, 27, 29, 30
W 9/3/03
Read sections 2.1 and 2.2. In your reading, make sure you understand the discussion following Example 3 (bottom of p. 44 to top of p. 45). Do problems 2.2/1-5.
F 9/5/03
2.2/ 6, 8, 9, 11, 13, 16-18, 22, 23. "Solve the equation" means "find the general solution of the equation". Following Friday's lecture, you should go back and check whether your general solutions, in the problems above that asked for them, omitted any equilibrium solutions. (I will say what that means on Friday.)
M 9/8/03
2.2/ 27abc, 29, 30-34
2.3/1-6, 7, 8, 13-15
W 9/10/03
2.3/17-20, 23, 24, 27a, 28, 30-35. In #33, note that what you might think is only a minor difference between the DE's in parts (a) and (b)--a sign-change in just one term--drastically changes the nature of the solutions. When solving differential equations, a tiny algebra slip can make your solutions utter garbage.
F 9/12/03
Read section 2.4 through the statement of Theorem 2 (p. 66). Do problems 2.4/1-8.

Read the handout "A terrible method for solving exact equations", obtainable from the Web.


M 9/15/03
Read the rest of section 2.4 and do problems 2.4/11, 12, 16, 17, 19, 20-22 (note that #22 is the same DE as #16, so you don't have to solve a new DE, you just have to incorporate the initial condition into your old solution), 27a, 28a,32.
W 9/17/03
Read section 4.1 and section 4.2 through Example 2 on p. 162 (we are skipping Chapter 3). Do problems 4.2/1-8. For now, assume that the methods used in Examples 1 and 2 give the general solution to the DE's in these problems. (This is a true fact that we will justify next week.)

The cutoff for Friday's exam is the assignment above, plus the material covered in class today. Wednesday's class meeting will just be question-and-answer (your questions, my answers); there will be no new material covered.


F 9/19/03
FIRST MIDTERM EXAM. Each student must take the exam during the period for which he/she is officially registered. Students who have not been attending class regularly should bring their Gator 1 cards for identification purposes.

To ensure that the playing field is level for my two sections, students in the 5th-period section will have to sign this pledge: ``I will not communicate, directly or indirectly, any information about this exam until after Dr. Groisser's 7th period MAP 2302 class has completed its exam today (2:45 p.m.). This prohibition includes discussing the exam and/or comparing answers with my classmates prior to the end of 7th period. I understand that the penalty for violating this rule is a failing grade for this course.'' Students in the 7th-period section will have to sign this pledge: ``I have not received any information today, directly or indirectly, concerning the exam given today to Dr. Groisser's 5th period MAP 2302 class. I understand that the penalty for violating this rule is a failing grade for this course.''


M 9/22/03
If you had any unpleasant surprises on Friday's exam, please re-read the section on pre-requisites on the class home page, and the sections on homework, workload, attendance, and miscellany on the syllabus. You may also want to re-read the handout "Taking notes in a college math class".

Never try to figure out the minimum amount of work you need to do to get the grade you want. Your goal should be to put yourself in a position to get 100% on every exam, regardless of what subset of fair-game material ends up being represented on the exam, and regardless of what form the questions take. If you make this your goal, you will learn and retain far more material, and get far better grades.


W 9/24/03
The assignment due last Wednesday should not have included problems 4.2/3,4; I overlooked that these two were of "repeated root" type and therefore not doable by the methods of Examples 1 and 2. I apologize if these two problems confused anyone. I'm surprised nobody asked me about them during Wednesday's review.

Read the box "Repeated Root" on p. 165 and Example 3 on pp. 165-166. We will justify the assertion in the "Repeated Root" box at a later date; just assume it's true for now. Do problems 4.2/3, 4, 9, 10, 13, 14, 17, 18, 20.


F 9/26/03
1. Read everything in section 4.2 that you haven't read yet.

2. Do non-book problems 3-6.


Exam 1 statistics: on the class home page you will find a link to the grade-scale page for your section. On the grade-scale page, you will find (for a limited time) a link to the complete list of scores on the exam (just the scores; nobody's name, ID#, etc.). On Friday I will return the graded exams. I do not email grades or answer any questions about exams by email, so please wait till Friday's class to ask me anything about the exam.

Problem-session Friday.This week I'll again hold a problem session Friday 9th period, LIT 203. After all questions related to recent homework have been answered, if there's time left I'll answer questions about the exam problems.


M 9/29/03
4.2/21,22,26, 27-33, 39, 40
W 10/1/03
No new homework
F 10/3/03
In addition to the homework assigned in class, read section 4.3 and do problems 4.3/1, 4, 6, 7, 9-12, 17, 18, 28, 30, 38, 39.
M 10/6/03
Read section 4.5 pp. 186-189 through the end of Example 2, excluding Example 1. We will cover section 4.4 after we have done most or all of section 4.5, but most of the examples in 4.5 assume (naturally) that you've already read 4.4; except for Example 2 they will not make sense to you yet. Do problems 4.5/1-8.
Special Note
Attendance has dropped quite a bit since the first exam (even counting the large and ever-increasing number of students who've been arriving late) although noone has dropped the class. If you did poorly on the first exam and are 100% sure you're going to drop the class, then of course it doesn't matter whether you attend or not. However, if there is any chance that you are not going to drop, you should be increasing the frequency of your attendance, not decreasing it. I have never had a single student who improved his or her grade by attending fewer classes after doing badly on an exam. In fact, I don't think I've had a student who did badly on a first exam even maintain his or her grade after reducing his or her attendance rate (except for students who were already running E's, who maintained their E's just fine).
W 10/8/03
Read section 4.4 and do problems 4.4/1-8, 9-11, 14. Note: you will not be able to do problems 1-8 until you have read at least as far as the box at the top of p. 184.

Included in the next one or two assignments will be all of the remaining problems in section 4.4 through problem 32, so if you feel ready for these based on your reading, you can go ahead and start on them. Problems 9-11 and 14 can be done using the ideas in the examples already presented in class; most of the others can't. Most of the problems in the 9-26 will be more time-consuming than the ones above, so getting some of them out of the way early would be a good idea.


F 10/10/03
4.4/13, 18, 25

Reread p. 187, read Example 3, p. 189 (don't worry about the first three lines; just start with equation (9)), and do problems 4.5/9-16, 20, 25-29. READ INSTRUCTIONS--problems 9-16 require no significant computation!

On Friday I will hold a homework Q&A session 9th period in LIT 203 (same time and place as before).


M 10/13/03
4.4/12,14-17,19-26.

4.5/23,24,30, 31-36.

Read section 4.6 and attempt to do as many problems as you can from 4.6/1-5, 11-15. I think you will find the problems easier after Monday's lecture, even though the lecture will have essentially the same content as section 4.6 of the text. However, I'm assigning these problems now because it is important that you not wait till after Monday's lecture to start trying problems that involve Variation of Parameters (the subject of 4.6). Your coming exam will include the material in section 4.6, and it takes time to absorb this material.


W 10/15/03
4.6/6-10, 16-18, 19 (first sentence only), 21, 25
F 10/17/03
SECOND MIDTERM EXAM. (Note change from date announced in syllabus). Again, students whom I don't recognize will need to show picture ID, and all students will be required to sign a no-communication pledge just as for the first midterm.
M 10/20/03
Read section 7.1 and 7.2 through example 2. (We are skipping ahead to chapter 7.)
W 10/22/03
Finish reading section 7.2 and do problems 7.2/1-8.
F 10/24/03
7.2/9-12, 21-23,26-28, 29a-d,f,g,j
M 10/27/03
7.2/13-20
7.3/1-8,31
W 10/29/03
7.3/9,10,25
7.4/1-10, 15, 16, 20 (Note: there is a review of Partial Fractions on pp. 370-374), 21-24, 26, 27
F 10/31/03
Read web handout "Partial fractions and Laplace Transform problems" (pdf file).
Do problems 7.5/1-8,10, 15,21,22,29.

To celebrate Halloween we will have a homework-review session Friday afternoon (4:05 p.m., LIT 203). Yes, the room used to be haunted, but it's been at least a couple of years since any ghosts appeared and dragged terrified students to their doom.


M 11/3/03
Read section 7.6 and do problems 7.6/1-4,11-18.
Because the second midterm was postponed, I will postpone the third midterm until Fri. Nov. 14. The midterm will cover at least through section 7.8.
W 11/5/03
7.6/5-10, 29-31, 33, 35-37, 39
M 11/10/03
(Amended 11/5/03.) I'm making this update without access to a textbook, and I won't have access to one till Monday, so I can't say specifically which of the problems from 7.8 will be due Monday and which will be due Wednesday. Your assignment for Monday is to read section 7.8 and do as many of the problems below as you can. Some students find the later problems (the IVP's) easier than some of the earlier problems in the section. The problems you don't finish by Monday are part of your assignment due Wed. Nov. 12.

7.8/1-12, 13-15, 17-19, 21-23, 30


W 11/12/03
See assignment for Monday 11/10/03
F 11/14/03
THIRD MIDTERM EXAM. (Note change from date announced in syllabus). The exam will cover sections 7.1-7.8 excluding section 7.7, and excluding the material in section 7.6 on the Gamma function (pp. 393-394).

Again, students whom I don't recognize will need to show picture ID, and all students will be required to sign a no-communication pledge just as for the first midterm.


M 11/17/03
Read section 7.7.
W 11/19/03
7.7/1-4,6,9,13, 15, 20.
F 11/21/03
7.7/23-28.
Read sections 8.1 and 8.2.
Note
We will be meeting and covering new material on Wed. Nov. 26.
Grade-scale changes on Exam 3
It has come to my attention (thanks to one of the few students who comes to my office hours) that although I carefully covered in class the topic of Laplace transforms of periodic functions, I did not assign any of homework problems on this topic that I thought I had assigned on this topic, 7.6/21-28. Consequently I am adjusting the contributions from Problem 4b (which was worth 6 points) to the grade scales on third midterm. This does not affect the A or D cutoffs (A students were expected to get 5/6 on this regardless of whether it was assigned for homework; D students were expected to get 0/6), but does affect the B and C cutoffs (B and C students had been expected to get 4/6 and 2/6 respectively; I have changed this to 3/6 and 0/6). Thus I am revising the B cutoff downward by 1 point and the C cutoff downward by 2 points. These changes are now reflected on the grade-scale pages for Section 3226 (5th period) and Section 5010 (7th period).
M 11/24/03
8.1/9-12
8.2/1-6 (find only the open interval of convergence; don't worry about the endpoints), 7,8
W 11/26/03
8.2/9-14,17,19,21,22,23,24,27.
Read section 8.3.
M 12/1/03
8.1/1,2,4,8
8.2/16,31,34,37,38 (better hint: integrate the series for 1/(1+x) and figure out what to do next).
Read section 8.3.
Eat.
Have fun and think a lot about differential equations. Oh, excuse me, I'm being redundant.
W 12/3/03
8.3/1,3,5,7-10,11-14,18,20-22,24,25,33
F 12/5/03
8.3/32,34.
8.4/1-6 (in #6, note that the equation "1+x3=0" has two non-real roots in addition to the real root -1), 15, 21,23,25, 29 (in #29 be careful not to use the letter n as a summation index since it already has an assigned, different meaning in this problem).

Read section 8.5.


M 12/8/03
8.4/7,9,12,18.

4.3/38,39,43 (the section number is not a misprint; these problems on pp. 178-179 are related to the equations studied in section 8.5).

Do non-book problem 7.

8.5/1,3,4,6, 13. Do #13 two ways: (a) by variation of parameters, as suggested in the book, and (b) by the method of 4.8/38--39. Decide which method you find easier, in case you're ever faced with such a problem without a hint as to how to do it. (We have not yet discussed section 8.5 in class, but reading section 8.5 was part of your previous homework assignment, so you should have no trouble with these problems. I will review this material briefly on Monday before moving on to section 8.6.)

Read section 8.6.


W 12/10/03
8.6/1,3,7, 11-13, 19,20, 25
Final Exam
Each section will have its final exam in the classroom in which it has met all semester. The dates and times for the exams are as announced in the syllabus. ( For the 5th-period section: Thurs. Dec. 18, starting at 3:00 p.m. For the 7th-period section: Wed. Dec. 17, starting at 12:30 p.m. Make sure you show up at the right date, time, and room for the section in which you're registered.)
You will be lent the same Laplace Transform table that you used on the last midterm.

On the sample exam handed out in class (last year's final), cross out problems 4, 11, and 12; these require material that I did not cover this year.

I'll have an office hour Fri. 10:30-11:30 a.m. as well as my usual afternoon hour.


Office hours during finals week
Monday: 11:00 a.m. - 12:00 noon and 3:00 p.m. - 4:00 p.m.
Tuesday: 10:30 a.m. - 12:00 noon and 2:00 p.m. - 3:00 p.m.
Wednesday, Thursday, Friday: no office hours
Receiving your grade 1. As soon as I determine the course grades, I will post them to ISIS. Prior to that time calling me, emailing me, or stopping by my office will only slow the grading process.
2. I will not send or discuss grades by email. As soon as possible after I submit the grades to ISIS, I will post final-exam statistics and course-grade statistics on your grade scale pages ( 5th period and 7th period ).

If you have a question about your grade or would like to look at your graded exam, please stop by during my office hours in January (not yet determined; check my schedule page in January). I will be back starting Jan. 5, but during the first week or two of classes there may be a line of students waiting to see me.



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