## Overview

Instructor | Dr. Armin Straub
MSPB 313 straub@southalabama.edu (251) 460-7262 (please use e-mail whenever possible) |

Office hours | MWF, 9-10am, 11am-noon, or by appointment |

Lecture | MWF, 8:00-8:55am, in MSPB 410 |

Midterm exams | The tentative dates for our two midterm exams are:
Friday, February 15 Wednesday, March 27 |

Final exam | Monday, April 29 — 8:00am-10:00am |

Text |
Linear Algebra with Applications,
by Jeffrey Holt (W. H. Freeman, 2013) |

Online grades | USAonline |

Syllabus | syllabus.pdf |

## Lecture sketches and homework

To help you study for this class, I am posting **lecture sketches**. These are not a substitute for your personal lecture notes or coming to class (for instance, lots of details and motivation are not included in the sketches). I hope that they are useful to you for revisiting the material and for preparing for exams.

After most classes, **homework** is assigned and posted below.

- You should aim to complete the problems right after class, and before the next class meets.

A 15% penalty applies if homework is submitted after the posted due date. - Homework is submitted online, and you have an unlimited number of attempts. Only the best score is used for your grade.

Most problems have a random component (which allows you to continue practicing throughout the semester without putting your scores at risk). - Collect a
**bonus point**for each mathematical typo you find in the lecture notes (that is not yet fixed online), or by reporting mistakes in the homework system. Each bonus point is worth 1% towards a midterm exam.

The homework system is written by myself in the hope that you find it beneficial. Please help make it as useful as possible by letting me know about any issues!

Date | Sketch | Homework |
---|---|---|

01/07 | lecture01.pdf | Homework Set 1: Problems 1-5 (due 1/18) |

01/09 | lecture02.pdf | Homework Set 1: Problem 6 (due 1/18) |

01/11 | lecture03.pdf | Homework Set 1: Problems 7-8 (due 1/18) |

01/14 | lecture04.pdf | Homework Set 2: Problems 1-3 (due 1/27) |

01/16 | lecture05.pdf | Homework Set 2: Problems 4-5 (due 1/27) |

01/18 | lecture06.pdf | Homework Set 2: Problems 6-9 (due 1/27) |

01/23 | lecture07.pdf | Homework Set 3: Problems 1-3 (due 2/3) |

01/25 | lecture08.pdf | Homework Set 3: Problems 4-6 (due 2/3) |

01/28 | lecture09.pdf | Homework Set 4: Problems 1-2 (due 2/8) |

01/30 | lecture10.pdf | Homework Set 4: Problems 3-4 (due 2/8) |

02/01 | lecture11.pdf | Homework Set 4: Problems 5-6 (due 2/8) |

02/04 | lecture12.pdf | Homework Set 5: Problems 1-2 (due 2/15) |

02/06 | lecture13.pdf | additional homework next class |

02/08 | lecture14.pdf | review quiz (solutions below); do Example 74 |

02/11 | lecture15.pdf | Homework Set 5: Problems 3-4 (due 2/15) |

02/13 | review | get ready for the midterm exam on Friday:
midterm01-practice.pdf (solutions below) |

02/18 | lecture16.pdf | Homework Set 6: Problems 1-2 (due 3/6) |

02/20 | lecture17.pdf | Homework Set 6: Problem 3 (due 3/6) |

02/22 | lecture18.pdf | Homework Set 6: Problem 4 (due 3/6) |

02/25 | lecture19.pdf | Homework Set 6: Problem 5 (due 3/6) |

02/27 | lecture20.pdf | Homework Set 6: Problems 6-8 (due 3/6) |

03/01 | lecture21.pdf | Homework Set 7: Problems 1-3 (due 3/15) |

03/04 | lecture22.pdf | Homework Set 7: Problem 4 (due 3/15) |

03/06 | lecture23.pdf | Homework Set 7: Problems 5-7 (due 3/15) |

03/08 | lecture24.pdf | Homework Set 7: Problem 8 (due 3/15) |

03/11 | lecture25.pdf | Homework Set 8: Problems 1-2 (due 4/8) |

03/13 | lecture26.pdf | Homework Set 8: Problem 3 (due 4/8) |

03/15 | (bonus) quiz | Happy Spring break! |

03/25 | review | get ready for the midterm exam on Wednesday:
midterm02-practice.pdf (solutions below) |

03/29 | lecture27.pdf | Homework Set 8: Problem 4 (due 4/8)
review exam |

04/01 | lecture28.pdf | Homework Set 8: Problems 5-7 (due 4/8) |

04/03 | lecture29.pdf | finish homework; new homework next class |

04/05 | lecture30.pdf | Homework Set 9: Problem 1 (due 4/22) |

04/08 | lecture31.pdf | Homework Set 9: Problems 2-3 (due 4/22) |

04/10 | lecture32.pdf | new homework next class |

04/12 | lecture33.pdf | Homework Set 9: Problems 4-6 (due 4/22) |

04/15 | lecture34.pdf | Homework Set 9: Problem 7 (due 4/22) |

04/17 | lecture35.pdf | Homework Set 10: Problem 1 (due 4/26) |

04/19 | lecture36.pdf | Homework Set 10: Problems 2-3 (due 4/26) |

04/22 | lecture37.pdf | Compute the 3rd and 4th Legendre polynomial (see Example 168) |

04/24 | lecture38.pdf | start preparing for the final exam |

04/26 | review | get ready for the final exam!
final-practice.pdf (solutions below) |

## Sage

As part of this course, we will explore the open-source free computer algebra system Sage to assist with more involved calculations.

If you just want to run a handful quick computations (without saving your work), you can use the text box below.

(The pre-entered code shows how to solve Example 44 in lecture08.pdf.)

An easy way to use Sage more seriously is https://cocalc.com. This free cloud service does not require you to make an account or to install anything: after choosing *Use CoCalc Anonymously*, select *View Your CoCalc Projects...* (at the bottom of the page), create a project (choose any name for it), followed by *New* and *Sage worksheet* and start computing. (To save your work for later, you can create a free account.)

Here are some other things to try:

- Sage can compute QR decompositions. For instance, we can have it do Example 64 (see lecture12.pdf) for us:
A = matrix(QQbar, [[0,2,1],[3,1,1],[0,0,1],[0,0,1]]) A.QR(full=false)

The result is a tuple of the two matrices Q and R. If that is too much at once,`A.QR(full=false)[0]`

will produce Q, and`A.QR(full=false)[1]`

will produce R. (Can you figure out what happens if you omit the`full=false`

? Check out the comment under "Variations" for the QR decomposition in lecture12.pdf. On the other hand, the`QQbar`

is telling Sage to compute with algebraic numbers (instead of just rational numbers); if omitted, it would complain that square roots are not available.) - Sage can also compute singular value decompositions. For instance, Example 144 (see lecture30.pdf) can be done (numerically) as follows:
A = matrix(RDF, [[2,2],[-1,1]]) A.SVD()

The result is a tuple of the three matrices U, Σ and V. If that is too much at once,`A.SVD()[0]`

will produce U,`A.SVD()[1]`

will produce Σ, and`A.SVD()[2]`

will produce V. (The`RDF`

is telling Sage to compute with real numbers as floating point numbers with double precision; for other fields such as`QQbar`

, the SVD is not currently implemented.)

An easy way to use Sage more seriously is by creating an account at http://cocalc.com. This free cloud service does not require you to install anything, and you can access your files and computations from any computer as long as you have internet. To do computations, once you are logged in and inside a project, you will need to create a "Sage notebook" as a new file.

## Exams and practice material

The following material will help you prepare for the exams.

- Midterm Exam 1:

midterm01-practice.pdf, midterm01-practice-solution.pdf

midterm01.pdf, midterm01-solution.pdf - Midterm Exam 2:

midterm02-practice.pdf, midterm02-practice-solution.pdf

midterm02.pdf, midterm02-solution.pdf - Final Exam:

final-practice.pdf, final-practice-solution.pdf