Introduction to Differental Equations,
                Math 331, Spring 2009 (Sections 1 and 4)


prof: Robert Gardner
LGRT 1430
Ph: 5-0029
gardner@math.umass.edu
http://www.math.umass.edu/~gardner
(click on link to class web page)
office hours:  Wednesday: 12:30-1:30, Friday 9-10, and at other times, by appointment.
In addition to the above, I will have the following additional office hours:
Thurs, May 7 from 10:45 to 12:30
Thurs May 14 from 10:45 to 12:30

Class TA for remainder of term: Yannan Shen
1341 LGRT
e-mail: shen@math.umass.edu
Office hours:
Wed May 6 : 2 to 4 pm
Wed May 13: 4-6 pm
Mon May 18 2-4 pm

Review sessions for final exam:
Review I: May 13: 2-4 pm (room TBA) will cover Laplace Transform methods
Review II May 16  2-45 pm (room TBA) will cover topics from midterms I,II
Sample final exams with solution sheets will appear on supplementary information link soon.

Text: Elementary Differential Equations Boyce and DiPrima, 9th edition, 2008.
 
Remark:  I've compared the 9th edition to the 8th and 7th editions of Boyce and DiPrima. The there are some very minor differences between editions. The main issues arise in chapter 3, where the material in Section 3.3 of the 7th and 8th editions has been moved to section 4.1. In terms of the exercises, there are virtually no differences (other than the  page number) between most problems in the three editions, with the exception of several of the more challenging problems towards the end of each problem set. I think that students in section 1 and 4 could easily get by with the 7th or 8th editions, since I  list problems from the text on homework sheets by section number and problem number, and generally don't ask you to  look at the "challenge problems". Also, problems from the text will generally be left as practice problems (not to be turned in), and graded homework will usually be based on problems I make up. Thus I think that using an earlier addition would cause at worst, cause some minor inconvenience now and then, but form the most part, would not cause any problems and might be a cost-efficient compromise. However, other instructors may use the text in different ways that may make it more difficult to use an earlier edition. If there is some chance you will be switching to a different section, I would advise staying with the 9th edition.


Homework: Homework sets consisting of reading assignments, problems to be turned in for grading, and additional practice problems that should not be turned. I will e-mail the assignments to using the oit class e-mail, and they can also be viewed/downloaded from a link on the class web page. Practice problems generally cover material discussed in the lectures and are similar to assigned problems and can be use both to get extra practice and as a way to review for exams.  Only the assigned problems on homework sets should be turned in during the lecture of the due date.

Homework Grading:
It is likely that only a sample of the assigned problems will be graded on each assignment. The grader will be instructed not to substitute a similar problem if one of the problems selected to be graded is not turned in. Assignments should be  written up neatly using paper not torn out of spiral notebooks, and multiple pages should be stapled together. The grader will have the right to give zeros to papers that do not follow these guidelines. Each homework set will have a maximum possible score of 20 points,  and there will be about 10 homework sets in all. There will be roughly 100 students in my sections of m331. Accordingly, it will be impossible to accept late homework, regardless of the reason for its being late.  I will therefore drop the three lowest homework scores, (including any zeros for homeworks that were not turned in) when calculating your average homework grade at the end of the semester.  Students who cannot attend the class can turn in their paper by leaving it in envelopes marked 331 homework for each section that will be  attached to the bulletin board opposite my office in LGRT 1430. The envelope will be removed when each set is given to the grader: that will be the absolute cutoff time for my accepting a homework submission, since solutions will be posted on the web shortly afterwards. Homeworks left under my office door or left in my mailbox will not be accepted and will receive a grade of zero. The  average  of your best homework scores will be averaged at the end of the term and will be recorded as a percentile grade. For example, if there are 10 homework sets and the average of your best 7 scores came to 16/20, your percentile homework grade would be 80%.

Exams: there will be two midterm exams that will be scheduled during the evening at times and  locations TBA, and a final exam during the final exam period. The final exam will be comprensive; half of the final exam will cover new material; the other half will review material covered on the two midterms.

Makeup policy: I will follow the usual university guidelines for giving makeup exams. You should be prepared to provide documentation for missing a scheduled exam for illness etc.  Exam conflicts: I will use the "course number test" (the instructor of the  course with the lower last digit in its course number must give a makeup)  if a student with an exam conflict provides documentation available from the registrar's office that the course number test is satisfied no later than one week in advance of the exam date. Depending on the number of students having a conflict, there may be a group makeup exam at a time and locaction TBA. Failure to follow these guidelines may result in a grade of zero.

Final (letter) grades: the final, midterms, and homeworks (as percentile scores) will be weighted as follows in calculating your final percentile score.

Midterms I,II : 25% each
Final Exam: 30%
Homeworks: 20%

The letter grades will be determined from the above according to the following scale for the lowest possible percentile grade for each letter grade:

A    90
A-   87
B+  83
B    80
B-  77
C+ 73
C   70
C-  67
D+ 63
D  60
F  59 and below

Class performance on each individual exam will be reviewed. If the median grade on an exam falls significantly below  70% (C), there are some situations in which I may decide it is appropriate to scale the numericall scores of that  exam.