Being a weblog devoted to a variety of topics. Including Mathematics. And Mathematical Finance. Sometimes with homework.

Monday, October 31, 2011

21-122: Week #10

The reading and homework assignments fr Week #10 have been posted. You can follow the link from the Schedule Page.

Wednesday, October 26, 2011

21-122: Week #9 Homework Due today

There is, I guess, a bit of confusion about the deadline for this week's homework assignment. It is due today. There is a misprint in one place on the assignment page, that seems to indicate it can be turned in during tomorrow's recitation. As I announced in class on Monday, and last Wednesday, and the Monday before that, the assignment is due today.

Monday, October 24, 2011

21-122: Mid-Semester Grades

I've finished assigning mid-semester grades, and I wanted to take a moment to describe exactly how that was done. As you know, your midterm exam average accounts for 60% of your grade, and your homework average for 15%. I've computed a numerical average for each of you using the following formula:

Avg = ( .60*[Exam #1 Grade] + .15*[Homework Average] )/(.75)

So your exam score counts for (60/75)ths of your grade, and your homework average counts for (15/75)ths. Then I computed grade cutoffs for these averages, by averaging the grade cutoffs the same way I computed your averages, i.e.

X-cutoff = ( .60*[Exam #1 X-cutoff] + .15*[Homework Average X-cutoff] )/(.75)

where X may be A, B, C or D. To assign +/- grades, the B and C ranges were divided into thirds, and the A and D ranges were divided in half. (There is no A+ and no D- grade.)

One final comment: As I was entering the final grades this afternoon, I realized I had made an error when calculating grades yesterday that systematically raised peoples averages a bit. I've corrected for this, and so some of you who saw your grade yesterday may notice it has gone down one increment (in a small number of cases more). I apologize for this apparent downgrade, but I want to make sure your grade represents where you really stand in the course.

Wednesday, October 19, 2011

21-122: Week #9

The reading and homework assignments for Week #9 have been posted. You can follow the link from the Schedule page.

Wednesday, October 5, 2011

21-122: Dfield

Today in class, I introduced dfield, and online Java applet that will draw direction fields, and plot the graphs of solutions (approximately, it uses numerical techniques; it doesn't solve the differential equations). A google search also turns up an instructional YouTube video about dfield. You may want to take a look at that, too.

21-122: Final Exam

The final exam has been scheduled; it's not particularly good news. Our exam is scheduled for Tuesday, December 20, from 8:30-11:30am. You should check the schedule to see if you have any conflicts among your exams. If you have three exams starting within 25 hours, your are also entitled to some relief. I will not offer the exam at an earlier time, but I can schedule a makeup exam later in the day if necessary to resolve conflicts.