# JHR's MA222 page

## MA222 Differential Equations II

MTRF 9, G317
John Rickert, Associate Professor of Mathematics
Office: G-215A, Crapo Hall
Phone: (812) 877-8473
Campus mail: CM 141
e-mail: john.rickert@rose-hulman.edu
Office hours: MTRF 8, or stop by and see if I'm in. My schedule
Textbook: Differential Equations, Polking, Boggess, and Arnold.(2nd ed.)
The Final Exam is Wednesday, November 18, 6:00PM-10:00PM in G220.

### Homework

Today's homework (for tomorrow's class)

For Friday, September 4: Section 5.1 #3,5,9,17,19,23,29. Turn in these exercises on Monday.
For Monday, September 7: Section 5.2 #5,7,19,23,31,35,43.
Turn in the Section 5.1 exercises.
For Tuesday, September 8: Section 5.3 #3,4,7,13,19,25,31.
Think about the inverse LaPlace transform of (s2+1)-2.
For Thursday, September 10: Section 5.4 #1,2,3,7,11,15,23,27,37. Turn in these exercises on Friday.
There will be a Quiz at the beginnning of class Thursday. You may use Maple and the LaPlace transfiorm table on page 204. The average score on the quiz was 28.3 out of 40. Equivalent grades are A 35-40, B 30-34, C 25-29, D 20-24, F <20.
For Friday, September 11: Section 5.4 #10,20,33,38,39,42; Section 5.5 #1,5.
Turn in the Section 5.4 homework exercises discussed Thursday.

For Monday, September 14: Section 5.5 #3,11,13,20,23,27,31,36. Turn in these exercises on Tuesday.
For Tuesday September 15: Section 5.6 #1,2,3,7,9.
Turn in the Section 5.5 homework exercises.
We will have a quiz covering through Section 5.4.
for Thursday, September 17: Section 5.7 #7,10,11,17,18.
The hitting-a-spring-mass-with-a-hammer worksheet is available online.
Check your ANGEL mail for any corrections to the summaries that you turned in at the end of class Thursday.
For Friday, September 18: Section 5.7 #19,27,29; Section 5.9 #1,5,6.
For Monday, September 21: Turn in your work on the hammer delta-function worksheet.
Tuesday, September 22: Exam #1 The average score on exam #1 was 95.8/120. Equivalent letter grades are A 100-104 B 88-99 C 76-87.
For Friday, September 25: Section 8.1 #7,11; Section 8.4 #1,7,11.
For Monday, September 28: Work on the problems on the worksheet. Turn in these problems on Tuesday.
For Tuesday, September 29: Section 9.1 #3,13,29,34,39,45,53.
Turn in the problems on the worksheet. For Thursday, October 1: Section 9.2 #1,3,7,9,59.
There will be a quiz on systems of differential equations on Monday. Use of Maple will be allowed. The average was 34.1/40. Equivalent grades are A 36-40 B 32-35 C 28-31 D 24-27.
For Friday, October 2: Section 9.3 #1,3,7,17,21. Turn in these exercises on Monday.

For Monday, October 5: Section 9.4 #1,5,9,13,17,26.
Turn in the Section 9.3 homework.
For Tuesday, October 6: Section 9.5 #3,9,23,29,43,51,53,54. Turn in these exercises on Friday.
For Friday, October 9: Turn in the Section 9.5 homework.

For Tuesday, October 13: Section 9.9 #3,7,15,30.
For Monday, October 20: Section 10.1 #1,5,9,13,19.
For Tuesday, October 21: Section 10.2 #1,5,11,16,20,21.
For Thursday, October 22: Section 10.6 #17,19,30; Section 10.8 #1,2.
Friday, October 23: Exam #2 average was 109.4/135. Equivalent scores are A 122-131 B 108-121 C 94-107 D 81-93.
For Monday, October 26: Section 6.1 #1,3,7,17,30.
For Tuesday, October 27: Section 11.1 #1,6,10,14,18,20,25,29,30,36.
For Thursday, October 29: Section 11.2 #1,5,13,17,27,28.
For Friday, October 30: Section 12.1 #4,17,19-22. Turn in these exercises on Monday.

For Monday, November 2: Section 12.1 #7,14.
For Tuesday, November 3: Section 12.2 #2,4,6,9,16,18.
For Thursday, November 4: Section 12.3 #3,7,10,14,22,26.
Friday, November 6: Exam #3. Equivalent grades are: A >= 140 B 120-139 C 100-119 D 80-99 F <80.

For Tuesday, November 10: Work on the LaPlace Transform Worksheet.
For Friday, November 13: Review MA222. Bring questions to class for review session.

### Notes

We will be covering
• LaPlace Transforms
• Systems of First order Differential Equations
• Approximations
Some useful Maple commmands:
assume(s>0)     tells Maple to assume that the variable s is positive.
convert( 1/(s*(s-1)), parfrac)     determines the partial fraction expansion of the expression.

### Course Policy

Material added since the beginning of class will be in purple
This class will have three in-class exams - most likely during the 3rd, 6th or 7th, and 9th weeks.
Note: I don't set grades using a 93/86/77/70 "straight scale" system. I plan to challenge you to excel. This means that the exam averages will generally be lower than what you are used to.
The final exam will be given during finals week. If you are making arrangements for travel home, you should make sure that they will not conflict with the final exam schedule. If your parents will be purchasing airline tickets for you, you should contact them and remind them not to schedule you on a flight that might cause you fail a class.
The weights for the grade are given below.
There may be two other types of quizzes given in class: announced and unannounced.

A stapler is probably a good investment for most of you. Multi-page homeworks should be stapled together, not mutilated.
Homework will typically be due at the beginning of class on the due date. Homework may be turned in later but will be penalized based on just how late it is - typically 10% off per day. i.e. 10 days later, it's too late to get a makeup homework turned in.
When writing up homework, you should circle (or otherwise clearly indicate) your answers. If the homework is on a worksheet that is passed out to the class, you will generally be expected to write your answers on a separate sheet of paper, in a well-organized fashion. Answers should be written on the worksheet only if answer blanks have been specifically provided.
If you have any questions while I'm not around, you may e-mail me at rickert@rose-hulman.edu and I will reply as soon as I can.

You should come to class prepared. This means that I expect you to have done the homework, brought your book to class and launched Maple at the beginning of class.

• If you don't understand something, ASK
• If I'm going too fast, STOP ME. I enjoy mathematics. When I get on a roll, I tend to keep going.
• SHOW YOUR WORK. The correct answer will only be worth 1 point. I want to verify that you understand the process.
• If you are having problems understanding the material, see me or go to the learning center.
I will assign some `group' projects in this class. Groups will consist of either three or four members. Write-ups from smaller or larger groups will not be accepted unless prior approval has been given.
Write-ups should be neatly presented. Write-ups returned on the information sheet handed out to the groups will not be accepted. Write-ups handed in at the end of class may be hand-written. Write-ups for work outside of class should be typed. Maple code may be included as part of an appendix or in figures, but should not be considered as a `formal' write-up. Similarly, `scratch-work' is unacceptable. Neatly written partial results may be turned in, but scribbles will reduce your grade.

### A summary of the grade weights

There will be three in-class exams worth 18% each
The final exam will be worth 36%
Quizzes and homework will be worth 10%

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