# 21-241: Matrix Algebra

### Description

Linear algebra covers material which is essential to anyone who does any mathematical computation in engineering and the sciences. In application and in class, the subject divides naturally into two parts: computation and formal structure. These are intimately related, but operationally distinct: on the one hand, computations with matrices and linear equations can be made into efficient algorithms, in mental code or in computer code, and, once created, these can be carried out with little attention to the theory. On the other band, in order to understand, to choose and then correctly optimize the applications of linear algebra, it is necessary to see the underlying formal algebraic structure. What does this mean for this course? Your challenge will be to master the algorithmic aspects of the subject, without thinking that this is all that there is to the subject, and to deal with the underlying formal structure by using the concrete model of matrices and vectors as a guide and as a tool.

### News

Monday 9 May: I'll be in my office this afternoon from 1:00-3:00, if you have any last minute questions.

Sunday 8 May: Throughout the semester I've tried to keep the graded homework and solutions organized. There is a separate envelope for every solution set. The graded homework also has separate envelopes for Section A and Section B.
If you come along and take everything out of the envelopes, spread it all over the table, and leave it that way it completely defeats the purpose. The next person who comes along (your classmates) have to sort through your mess to find what they need. When I get to my office I have to sort out your mess and put everything back in order.
Whoever you are, why don't you take 2 seconds and think about someone besides yourself.
Sunday 8 May: I've added some hints and suggestions for the additional review problems. You can find a link from the final exam review page.
Friday 6 May: It's come to my attention that although I updated the reveiw page with information about the Review Session, I didn't post a note here, so here goes: The Review Session is Sauturday 7 May, from 7:30-9:00pm in DH 1212.
Thursday 5 May: Solutions to Exam #3 are now available outside my office door, and I've added some additional problems to the Final Exam reveiw page.
Wednesday 4 May: Graded Homework #11's (and late Homework #10's) are now available outside my office door.
Tuesday 3 May: Solutions to HW#11 are now available outside my office door.
Tuesday 3 May: I've posted a review page for the Final Exam. Follow the link from the Schedule page. The final review covers only (or primarily) the material covered since Exam #3. The Final Exam will be cumulative, however, so make sure you look back at the previous review pages as well.
Monday 2 May: This week I'll be holding office hours from 1:00-3:00 on Wednesday, Thursday and Friday. I'm also scheduling a review session for Saturday evening. If you need to see me at some other time, contact me, and we can most likely arrange something.
I'll be posting a final exam review sometime later today or tomorrow. It will cover only (or primarily) the material since Exam #3, but be aware that the final exam will be cumulative. You should go over the review pages for each of the previous exams as well.
Tuesday 26 April: The homework assignment is actually due this Wednesday, April 27. It is not due last December. I've updated the assignment page to reflect this fact.
Tuesday 26 April: There will be no additional problems added to this week's assignment. (The assignment page indicated there would be).
Thursday 21 April: The reading and (most of) the homework assignments for Week #12 #14 have been posted. Follow the link from the Schedule page.
Tuesday 18 April: Solutions to HW#10 are available outside my office door. I'll make the graded homework available as soon as I have them all. I'd also like to thank you all for your understanding and support. I appreciate all your good wishes. Baby Ryan is doing a bit better today, the doctors are beginning to wean him off of his support a bit. He has a long way to go, but he is moving in the right direction.
Saturday 16 April: Your graded Homework #9's are available outside my office door. I don't have access to a photocopying machine over the weekend, but I'll get solutions put out on Monday.
Saturday 16 April: I've posted some old exam problems for you to work on. They're at the bottom of the review page. If you have difficulty with them, you can ask your questions at the review session on Monday evening, April 18, 7:30-9:00 in DH 1112.
Friday 15 April: As many of you may be aware, my wife gave birth to our second son on Tuesday, Ryan Patrick Handron. Since Tuesday evening, Ryan has been in the Neonatal ICU recovering from Pneumonia. He seems to be doing well right now, but he is very sick. In any case, this has slowed me down a bit at work.
I have your graded Homework #9's. Tomorrow morning, I should be able to get those grades recorded and put them outside my office door, so you can pick them up. I should also be able to post the old exam problems at the same time. I apologize for the delay, but I will get this done as soon as I am able.

Monday 11 April: The reading assignment for Week # 13 has been posted. I've also posted a review page for Exam #3. I'll update it before too long with some old exam problems, so check back.
Friday 8 April: The solutions to Exam #2 and HW#8 are available outside my office door.
Thursday 7 April: The reading and homework assignments for Week #12 have been posted . Follow the link from the Schedule page.
Thursday 7 April: I would like to remind you that Rebecca Lambert holds office hours for 21-241 on Monday, Tuesday and Thursday evenings. The exact times are: Monday 6:30-8:30pm (PH A18C), Tuesday 8:30-11:30pm (PH A18A), and Thursday 8:30-9:30pm (PH A18A). Please note that other classes have the rooms reserved at earlier times. Please wait until the scheduled time to enter the room. Thanks.
Thursday 31 March: The reading and homework assignments for Week #11 have been posted . Follow the link from the Schedule page.
Tuesday 29 March: Here are some updated statistics for the course. They include information about Exam #2. The updated "Cumulative Average" grade cutoffs may be of particular interest.
Monday 28 March: Correction: the previous note should have read "Do only parts (a), (b), (d), and (e).
Saturday 26 March: There is a minor update for the homework assignment for Week #10. You can skip part (c) of problem 5.1.22. Do only parts (a), (b), (c), and (d), and (e).
Friday 25 March: The reading and homework assignments for Week #10 have been posted . Follow the link from the Schedule page.
Friday 18 March: Check the Exam Review Page for updates: A review session will be held on Monday 21 March, from 7:30-9:00pm in MM A14. Also I've posted some old exam problmes.
Tuesday 15 March: Exam #2 will be given in class next Wednesday 23 March. A Review Page has been posted. Follow the link from the Schedule Page.
Tuesday 15 March: The reading assignments for Week #9 have been posted. Follow the link from the Schedule page. The class is falling a bit behind the schedlue. We are maybe a day or so behind where the schedule says we should be, but that is not so bad, I think. Just be aware of that as you prepare for class.
Wednesday 2 March: The reading and homework assignments for Week #8 have been posted . Follow the link from the Schedule page.
Wednesday 23 February: The reading and homework assignments for Week #7 have been posted . Follow the link from the Schedule page.
Tuesday 22 February: A multitude of statistics are available, including statistics for Exam #1.
Friday 18 February: The reading and homework assignments for Week #6 have been posted . Follow the link from the Schedule page.
Sunday 13 February: The Exam #1 Review Session will take place as advertised (Time: Monday 14 February, 7:30-9:00, Place: PH 100). I had indicated that there was some confusion with the reservation, but that has been cleared up.
Additionally, I have updated the old exam problems on the review page to include problems related to sections 2.2 and 2.3.
One more thing: You should also make sure to look over your homework assignments and the homework solutions (which are available outside my office door).
Thursday 10 February: Exam #1 will be given in class next Wednesday 16 February. A Review Page has been posted. Follow the link from the Schedule Page.
Thursday 10 February: The reading assignment for Week #5 has been posted. There is no written assignment this week. Use the extra time to study for Exam #1.

Thursday 3 February: The reading and homework assignments for Week #4 have been posted . Follow the link from the Schedule page.
Tuesday 1 February: For tomorrow's homework, the first "Additional Problem" should ask for the Standard Matrix for the given linear transformation.
Monday 31 January: Office Hours for the week of Jan 31 - 28 will be as follows: I (Dr. Handron) will hold office hours in my office (WEH 6214) on Monday from 2:30-3:00 and Tuesday from 1:30-3:00. Rebecca Lambert will hold office hours Mon. 6:30-8:30pm (in PH A18C), Tue. 8:30-11:30pm (in PH A18A), 8:30-9:30pm (in PH A18A).
Monday 31 January: The reading and homework assignments for Week #3 have been posted (and have been for a while). Follow the link from the Schedule page.
Monday 24 January: Office Hours for the week of Jan 24 - 28 will be as follows: I (Dr. Handron) will hold office hours in my office (WEH 6214) on Monday from 2:30-3:00 and Tuesday from 1:30-3:00. Rebecca Lambert will hold office hours Mon. 6:30-8:30pm (in PH A18C), Tue. 8:30-11:30pm (in PH A18A), 8:30-9:30pm (in PH A18B).
Friday 21 January: I would like to make a comment regarding your homework assignments and the Academic Integrity Policy. I encourage you to work with other students do understand the homework problems, though I require that you write your solutions independently. You are also allowed to consult other textbooks or online resources to gain a better understanding of the course material. If you do so, you should cite the sources you consult at the end of your homework paper.
Some of you may have access to homework solutions from previous semesters. Because there is likely to be some overlap with this semesters assignments, these are considered off-limits. You may not use them to help you with the assignments.
Thursday 20 January: The reading and homework assignments for Week #2 have been posted. Follow the link from the Schedule page.
Monday 17 January: You may wish to take note of the opportunities provided by Academic Development (412-268-6878).
Monday 17 January: This week's office hours will be as follows: I (Dr. Handron) will hold office hours on Monday and Tuesday, from 1:30-3:00, in WEH 6214. Rebecca Lambert will hold office hours Mon. 6:30-8:30pm, Tue. 8:30-11:30pm, 8:30-9:30pm, in WEH 6215.
Monday 17 January: In working on problem 1.3.31, it my be helpful to note the definition of "center of mass" in problem 1.3.29.
Tuesday 11 January: The reading and homework assignments for Week #1 have been posted. Follow the link from the Schedule page.
Monday 10 January: Welcome to the 21-241 Web site. You can navigate the site using the buttons to the left. The Schedule page shows the topics to be covered, and provides links to homework assignments. Be sure to read the Grading and Policy pages. They have a lot of important information.