06.21
  • H3 available. H3 marking scheme. Comments from TA:
    • I marked question 1, 2, 4, 5, 6, 7, 9, 10, and 11. Attached is the marking scheme detailing where I give points, in case any student asks.

  • List of sections for final exam posted.

06.20
  • Revised Office hours after end of term:
    • Tsai: 1:30pm-2:30pm, Friday June 22, Tuesday June 26, and Wednesday June 27.
    • TA David Kong: 10am-noon, Monday June 25, Math Annex 1118.

  • Practice final exams posted. Practice 6 revised.

  • Students are encouraged to complete the teaching evaluation surveys on the CoursEval website, https://eval.ctlt.ubc.ca/science before the surveys close at 11:59 PM on June 24, 2018. You login to the site using your CWL. Survey results will not be released to instructors until course grades have been submitted.

06.18
  • Office hours after end of term: 1:30pm-2:30pm, Friday June 22, Monday June 25, and Wednesday June 27.

06.15
  • The average of MT2, the second midterm exam, is 30.4 out of 45, or 68%. It is slightly lower than my target 70%. The standard deviation (Std Dev), 17%, is roughly the same as last year and MT1. For comparison, the distribution of MT1 is included in the following table and chart.

    		0-5 6-10 11-15 16-20 21-25 26-30 31-35 36-40 41-45 total average max Std Dev
    MT1 0 0 2 2 14 13 27 22 17 97 33.3 or 74% 45 16%
    MT2 0 0 2 7 14 23 26 12 10 94 30.4 or 68% 45 17%

  • Problem-wise statistics:

    		Q1 Q2 Q3 Q4 Q5 Q6 MT2
    max
    		 10 5 6 8 10 6 45
    average 6.7 2.5 3.2 6.4 8.0 3.7 30.4
    average % 67% 50% 54% 80% 80% 61% 68%
    Std Dev 30% 29% 36% 23% 21% 23% 17%

06.14
  • MT2 solution posted. MT2 will be returned tomorrow.

06.11
  • H2 available. H2 marking scheme. Comments from TA:
    • I have finished marking homework 2 and it is out of 39. I marked questions 1,3,4,6,7,8,10,11,13,14,15, and 16. Overall it is done quite well. Most students l$ 2-3 marks due to computational errors.

  • H3 and practice 5 posted. Note that H3 is due next Monday, so that we can retu$ it on next Thursday.

06.07
  • The second midterm exam (MT2) next Wednesday (June 13) will use the entire lecture time, 50 minutes. Its format will be similar to MT1. It will cover
    sections 1.9, 2.1-2.3, 2.5-2.6, 3.1-3.2, and 4.1.
    For your preparation, practice 4 and old MT2 have been posted. The solution to 2017 MT2 will be posted in the weekend.

06.04
  • There was a typo on the end time of the final exam. It is now corrected. It should end at 6pm, not 5pm. The total exam time is 150 minutes.

06.01
  • Repost final exam info: Our final exam will occur on Thursday June 28, 3:30pm-6pm, in LSK 200.

  • The average of MT1, the first midterm exam, is 33.3 out of 45, or 74%. It is slightly higher than my target 70%. The standard deviation (Std Dev), 16%, is roughly the same as last year. The solution to mt1 is posted.

    		0-5 6-10 11-15 16-20 21-25 26-30 31-35 36-40 41-45 total average max Std Dev
    MT1 0 0 2 2 14 13 27 22 17 97 33.3 or 74% 45 16%

  • Problem-wise statistics:

    		Q1 Q2 Q3 Q4 Q5 Q6 MT1
    max
    		 6 9 8 8 8 6 45
    average 5.4 7.3 6.2 6.1 4.4 4.0 33.3
    average % 89% 81% 78% 76% 55% 66% 74%
    Std Dev 18% 19% 27% 30% 40% 19% 16%

05.31
  • The first midterm exam will be returned on Friday June 1. The marking is done, but $ need to record the marks and do the statistics. Note that June 1 is the "last day for withdrawal from most Summer Session Term 1 courses with withdrawal standing of W recorded on a student's academic record."

05.28
  • The first midterm exam has 6 problems now, see MT1 page 1. The last one is Yes/No with no reason. Some other problems are Yes/No with reasons.

  • H1 available. Uncollected homework/exam will be placed in a box outside of my office.

  • H1 marking scheme. Comments from TA:
    The homework is marked out of 39. A detailed marking scheme is pushed onto the cloud and also attached to this email in case students ask where they lost marks. This one is pretty easy so most students got nearly perfect scores. Some observations are:
    1. When doing row reduction, a majority of students wrote out the row operations explicitly, ex. R1+0.5R2, R3+R1,... which I believe are for demo purposes during lectures only
      (Reply from Tsai: Actually I did ask them to mark the row operations explicitly and briefly. One way is to write
      R1 -> R1 + 0.5R2,
      another way is to draw an arrowed curve from R2 to R1 and write "x(1/2)" along the curve. Sometimes I did 2 row operations together in one step, like
      R1 -> R1 + 0.5R2,
      R3 -> R3 - R2
    2. A few students are confused about consistent/inconsistent and cannot determine which situation corresponds to which
    3. Lots of silly calculation mistakes, especially in row reductions and T/F

  • Our final exam will occur on Thursday June 28, 3:30pm-6pm, in LSK 200.

05.25
  • The first midterm exam next Wednesday (May 30) will cover sections 1.1-1.5 and 1.7-1.8.

05.23
  • The location of the TA office hours, 2-4pm Tuesdays, will be moved to Math Annex 1118 (MATX 1118), starting next Tuesday. Our TA, David Kong, told me that the office hour location yesterday, LSK 300B, was shared by several classes and hence was a bit noisy and hard to identify our class. Math Annex 1118 will be for MATH 221 only. I encourage you to attend the TA office hours since David is very good and dedicated. He is also younger and understand you better than me.

  • First midterm Exam next Wednesday (May 30) will use the entire lecture time, 50 minutes. For your preparation, I have posted practice 2 and two old midterm exams. The format of our first midterm exam next week will be similar to the 2017 exam, with 4 computation problems and one Yes/No problem. The Yes/No problem will have 6 questions with no need of justification. I will announce the topics to be covered on Friday. The solution to the 2017 exam will be posted in the weekend. Please read carefully "Rules for the exam" in the first page of the 2017 exam.

05.16
  • Because Lay's textbook is not in UBC bookstore yet, I've stored a pdf file of the first chapter of Lay's book, 3rd edition, in a cloud server hosted at UBC Math. Registered students will soon receive an email with its link, which will expire on 2018-07-16. If you are not registered and want the link, please email me.

  • There are many free online textbooks on linear algebra. The book by Jim Hefferon, Linear Algebra, is a well-known open-source textbook and has lots of good exercises.

  • Because next Monday is the Victoria Day, we will hold an additional office hour this Friday, May 18, 3-3:50pm.

05.14
  • Welcome to MATH 221 !
    Check this page frequently regarding any announcement for the course.

  • Please read the course outline carefully.

  • Email after lecture:

    Dear MATH 221 students,

    I am very sorry for the power disruption during today's lecture. It was an issue for the entire Buchanan A building, and it was unclear when it could be fixed. Hence it was simpler to cancel today's lecture. We will start on the Wednesday lecture from where we stopped today. We will not schedule a make-up lecture since it is nearly impossible for a class of 119 students. As a result, we may skip a section near the end of the course.

    Note, however, my office hours will start today at 3pm, and tomorrow at 1pm. Please get yourself familiar with the course homepage
    http://www.math.ubc.ca/~ttsai/courses/221-18Q2/
    Another issue found after today's lecture is that the textbook by David Lay was not ordered at the UBC Bookstore. I've contacted the MATH office to order the book, but it may take a week. Please note that, although my lectures will follow the book closely, you don't really need the exact book as the assignments/solutions will be typed and posted in the course homepage. For your study, it is better to read a textbook in addition to my lecture notes. I will try to find some free online textbooks and let you know on Wednesday. I also encourage you to look for Lay's book in the used books market. The third UBC custom edition has been used by UBC for many years and should have a big supply.