18.03  Differential Equations

In response to a question from one of you: 
There will no regrade process for the final exam this coming week as there was for the midterms.  Because many of you have left town already, only those of you still in town would have a chance to submit a regrade, which would not seem fair to me.  Also, it is simply impractical since many of the recitation instructors will have left town too.  Finally, we were quite careful in assigning final exam grades: the recitation leaders and I graded exams and checked scores for 11 hours straight on Thursday afternoon and evening.

So my policy is this:
There are no regrades for students who simply feel that they deserve more partial credit on a problem than was assigned.  The only situation in which the grade might be changed is if there was a page that the graders entirely forgot to grade, or a totaling error.  Moreover, such a change would be made only if it would amount to a 10-point difference or more on the exam.  I do not expect that there will be any instances of this at all.

Best,
Bjorn Poonen

Dear 18.03 students:

Below are the minimum scores needed to earn each grade in 18.03.  These are based on the numeric score computed as in my grading policy, and have nothing to do with the grade averages in Gradebook (which I have just disabled, I believe).  I follow the official MIT definitions of grades, which are as follows (I mention this since sometimes students expect grades to mean the same thing as in their high school, which is often not true):

A Exceptionally good performance demonstrating a superior understanding of the subject matter, a foundation of extensive knowledge, and a skillful use of concepts and/or materials.

B Good performance demonstrating capacity to use the appropriate concepts, a good understanding of the subject matter, and an ability to handle the problems and materials encountered in the subject.

C Adequate performance demonstrating an adequate understanding of the subject matter, an ability to handle relatively simple problems, and adequate preparation for moving on to more advanced work in the field.

D Minimally acceptable performance demonstrating at least partial familiarity with the subject matter and some capacity to deal with relatively simple problems, but also demonstrating deficiencies serious enough to make it inadvisable to proceed further in the field without additional work.

F Failed.

Here is the conversion table:

95 A+
88 A
82 A-
80 B+
74 B
69 B-
67 C+
63 C
60 C-
53 D
 0 F

To calculate your letter grade, follow the grading policy on Stellar to get the numeric score, round it to the nearest integer, and use the table above.  At the C-/D and D/F boundaries, I decided to round up up to a full percentage point.  If you can't figure out the grading policy, please don't all email me asking me to explain it; just wait a few days since the official letter grades will be available on WebSIS then.

I know that some of you had an off day on one or more of the exam dates, and that the letter grade might not reflect your actual understanding, but that is just the nature of this imperfect evaluation process, and there is nothing to do about it now.  If that's the case, you can expect to do better in future classes that rely on this material!  Anyway, I am impressed with how quickly and thoroughly the class as a whole learned the material.

You may view your graded final exam, but you may not take it home.  Your exam is being held either in your recitation instructor's office or in the Mathematics Academic Services office E18-366;  I'll ask each recitation instructor to let you know which.

I wish you all a great summer!
Bjorn Poonen

If you have an excused absence on one of the midterms, and the missing grade was to be replaced by the average of your other exams, then this will be taken into account in my calculations, but the calculations are being done in a spreadsheet outside Stellar, so you will not see that score appearing in Stellar.  Remember also that you should ignore the Stellar "cumulative grade".

Two of you mentioned to me that you are having problems accessing Gradebook.  If any of you have such problems, please click "Contact" on the Gradebook help page for technical support, since your grades are showing up fine for me, and I can't see any problem myself, so I don't know what's going on.

I expect to send out the letter grade conversion by tomorrow.

Best wishes,
Bjorn Poonen

P.S. I've gotten somewhat behind in responding to email the past few days because of the volume of email I've been receiving (and because I and the recitation instructors had an 11-hour grading session yesterday)!  I will eventually respond, however!

(I'm reposting this so that it moves to the top of the announcements.)

The final exam is Thursday, May 22, 9am-12 at Johnson Track (upstairs).  If you have a conflict or potential conflict with the exam, you must let me know immediately.

Listeners and other students not enrolled for credit should stay home; the exam and solutions will be posted on Stellar, so you can self-administer and self-grade it.

Please plan to arrive by 8:55am.  Visits to the restroom during the exam are permitted, but please try to minimize them by using the restroom beforehand!

No notes, books, or electronic devices are permitted.  All you need to bring are pencils or pens, and your student ID card, which is to be displayed on the desk during the exam.

When you show up for an exam, you are affirming that you are well enough to take it.  If you are sick, seek medical attention, stay home, email me and your recitation instructor as soon as possible, and contact S^3; assuming that S^3 sends me an excuse notice and that you have been doing passing work up to the final, you will receive a grade of O for 18.03, which will be converted to OX if your absence is approved by a dean; you will then have to retake an 18.03 final exam later on (the next one being the Advanced Standing Exam during Orientation Week before fall classes begin) to change it to a regular grade: contact Galina Lastovkina <galina@math.mit.edu>, 617-253-4977, room E18-366 if you have questions about this.

The following topics will not be covered on the final exam (but may be useful to you in later MIT subjects): generalized exponential response formula, degenerate (structurally unstable) phase portraits (you should know the case of a center, however), derivation of the heat and wave equations from physical laws, discretization of the heat equation, Google search, and topics introduced May 9 or later.  The exam covers all other topics discussed in lecture and recitation.  Practice problems are available in Materials on Stellar.

After the exam, solutions will be posted on Stellar.  Grades will not be sent by email.  Your final letter grade will be available online at WebSIS as soon as it is ready.

Good luck, everybody!
Bjorn Poonen