UBC MATH 215, Spring 2010, Announcements

Elementary Differential Equations I

UBC Math 215, Spring 2010, Announcements

04.14

04.09

The final exam will cover up to and include §9.3. The problems will be evenly distributed: Materials for MT1, MT2 and after MT2 will be roughly 1/3 each. Sample exams with solutions will be posted. Extra office hours TBA. Math Club exam packages are for sale. Their office is in Room 1119 in the Math Annex. See www.ubcmathclub.org for schedule.

04.07

Midterm exam 2: average 29.5 out of 40, standard deviation 8.4 (compare with midterm exam 1 average 25.3+1 with SD 7.4).

Comments from TA for homework 7:
Again a student forgot to put name on. One common mistake in 6.6 18: a few students didn't transform Y(s) back after solving the equantion on Fourier side.

03.20

Comments from TA for homework 6:
My selection is:6.3:13,23;6.5:4,6. Students did well. Most of them understand the procedure but computation is becoming harder at this point. They should be more careful. One student forgot to write name. I put the paper on the top. Let me know when you find out whose it is so that I can record the score.

03.19

03.17

The Mathematics Department will hold an information session for first- and second-year students at the time and location below: Mathematics Information Session Tue. Mar. 23 from 12:30 p.m. - 1:30 p.m. in Math 100 Topics to be discussed include degree programs involving mathematics at UBC (including a wide array of combined programs), careers involving mathematics, and general information about the Mathematics Department. FREE PIZZA AND POP WILL BE PROVIDED.

Second midterm exam will be held next Wednesday, Mar 24. It will cover sections §3.4-3.8 and § 6.1-6.6. There will be 4 problems. No calcalator and no notes. A sample midterm exam is posted. Partial selection of homework 7 on §6.6 will be posted.

03.15

Comments from TA for homework 5:
Students did a great job. No common mistake. But one thing I'd like to mention in problem 21, section 6.1 is that convergence to zero at infinity of the integrand does NOT imply the convergence of the integral. It's a necessary but not sufficient condition.

03.08

Comments from TA for homework 4:
My selection for homework 4 is 3.6:11,13 3.7:1,20 One common mistake: a few students didn't rewrite the equation as y^'' - 2t^{-2}y=3-t^{-2} and did not do the computations correctly.

02.16

Comments from TA for homework 3:
My selection is 3.2: 20; 3.3: 18; 3.4: 9, 26. Comment: Many students guessed what f and g are in 3.2 20. They only need to know the Wronskian of f and g to figure out what the Wronskian of u and v is, since W[u,v]=-4W[f,g].
One student forgot to put name on the paper. I put it on the top. Let me know whose it is then I can record it on the grading sheet.

02.12

02.08

THe first midterm exam: average 25.33 (63.3% of 40), standard deviation 7.43 (18.6% of 40).
Because the average is lower than ideal, and some students using the older edition of the textbook did not understand that the complex root case section 3.3 is included, I am making the following changes:
1. Everyone receives a free mark.
2. A new grading scheme for midterm exam part: Better midterm exam counts for 26%, worse midterm exam 14%, for the course grade.

02.01

Comments from TA for homework 2:
My selection is 2.6: 7, 25; 2.7: 2(a); 3.1: 26(a).
One common mistake in 2.6 25: students have trouble in computing the indefinite integral after they find the integrating factor. It involves integration by parts.
Office hours before midterm: Monday Feb 1, 2-2:50pm, Tuesday Feb 2, 11-11:50am and 2-2:50pm.

01.27

First midterm exam will be held next Wednesday, Feb 3. It will cover up to and including section 3.3. There will be 4 problems: 3 computational and one theoretical. No calcalator and no notes. A sample midterm exam is posted. Partial selection of homework 3 up to section 3.3 is posted.

01.25

Comments from TA for homework 1:
My selection is 2.1 13;2.4 1, 15, 22(a,b) Students did a great job! The only common mistake is that quite a few students missed the case y_{0}=0 in the problem 2.4 15.
Could you please tell students to print their names clearly on their homework, especially last name? It would be more efficient for my work if I don't spend time on reading their names.

01.18

There are IAM graduate students working at the drop-in tutoring centre in the Barber Learning Centre on Mondays and Wednesdays all day. You should ask for TAs who can answer questions on differential equations (there should be a sign).
In fact, there are IAM GTAs in most hours of the week (8 am to 4 pm Mondays to Thursdays and 8 am to 3 pm on Fridays), and you are welcome to drop in then as well.
The UBC/UMC (Undergraduate Mathematics Colloquium) is starting up again this week. We have a great list of speakers this term, including Mike (Bennett), Anthony (Peirce) and Bud (Homsy). You are encouraged to attend.
Mike Bennett will be giving the first talk on WEDNESDAY, JANUARY 20 from 3:00 to 4:00 in MATH 105, entitled
"Diophantine equations for fun (and profit?)"
An abstract and other information can be found at this link.

01.08

If you have registration issues, please visit this math department webpage. The Math Department Undergraduate Chair, Professor Rajiv Gupta, will help you during the Registration Assistance Session. Note that Math Instructors Do Not Have the Authority to Sign You Into Their Section.

01.04

Welcome to Math 215!
Check this page frequently regarding any announcements for the course.

Two copies of the 9th edition of the textbook have been put in the UBC Library reserve and are available for 2 hour loan. Reserve books are held at the Circulation Desk on the 2nd floor of the north wing of the Irving K. Barber Learning Centre.