Math 201

Linear Algebra
Fall 2021 Section S03

Current week
Instructor: David Perkinson (schedule)
Text: Linear Algebra, by Jeff Hefferon. (Solutions to exercises).
Syllabus
For details on office hours, the evening group problem sessions, and drop-in tutoring, see the top of our Moodle page.
Presentations: Short presentations on applications of linear algebra will delivered during the last week of classes. Here is the schedule.
Exams Sage code (from in-class computer examples)

Compiled course materials Math 201, 2021 (12/15/21).
Week 1: August 30 - September 3
Monday: Solving systems of linear equations (lecture, tex file, slides).
  • Reading: Chapter One, Sections I and III.
  • Practice problems: Chapter One, Section I: 1.17, 1.22, 1.27, 1.37 (challenge). (Note: do not turn in practice problems.)
  • To do list for Wednesday.

Wednesday: Reduced row echelon form (lecture, tex file, slides).
  • Reading: Chapter One, Sections I and III.
  • Practice problems: Chapter One, Section I: 2.18, 2.21, 2.24, 2.29, 2.32 (challenge), 3.15, 3.18, 3.25; Section III: 1.8, 1.10, 1.14, 1.15, 2.11, 2.20, 2.24. (Note: do not turn in practice problems.)
  • Attend the introduction to LaTeX session tonight on Zoom, 7–8 pm. The Zoom link can be found on our Moodle page.

Friday: Geometry of vectors in \(\mathbb{R}^2\) and \(\mathbb{R}^3\) (lecture, tex file, slides). Interesting article: What is a clock?

Week 2: September 6 - 10
Monday: Labor Day (no class).
Tuesday: Turn in Week 2 Tuesday (overleaf template) homework by 3 p.m.
My office hour today will be 12:30–1:25 p.m. today instead of the usual 1–2 p.m.
Wednesday: Vector spaces. (lecture, tex file, slides).
  • Reading: Chapter Two, Section I.
  • Practice problems: Chapter Two, Section I: 1.18, 1.19, 1.22, 1.28, 1.29, 1.40.

Friday: Subspaces and spanning sets I. (lecture, tex file, slides).
  • Reading: Chapter Two, Section I.2.
  • Practice problems: Chapter Two, Section I.2: 2.20, 2.21, 2.29, 2.44.
  • Turn in: Week 2 Friday (overleaf template) homework. (From now on, it is understood that homework is due by 3 p.m. unless otherwise stated.) [Recall: to prove that something is false, it is almost always best to give a concrete counterexample.]
Week 3: September 13 - 17
Monday: Subspaces and spanning sets II. (lecture, tex file, slides).
  • Reading: Chapter Two, Section II.1.
  • Practice problems: Chapter Two, Section II.1: 21, 23 (b).

Tuesday: Turn in Week 3 Tuesday (overleaf template).
Wednesday: Linear independence. (lecture, tex file, slides).
  • Reading: Chapter Two, Section II.1.
  • Practice problems: Chapter Two, Section II.1: 1.23 (c), 1.28, 1.29, 1.33 (ab).
  • See our Moodle page for a video explaining the algorithm covered at the end of today's lecture.

Friday: Bases. (lecture, tex file, slides).
Week 4: September 20 - 24
Monday: Dimension I. Exam 1 distributed after class today (due on Wednesday). (lecture, tex file, slides).
  • Reading: Chapter Two, III.2.
  • Practice problems: Chapter Two, III.2: 15, 17, 21.

Tuesday: No homework due today.
Wednesday: Dimension II. Exam 1 due before class today. (lecture, tex file, slides).
  • Reading: Chapter Two, III.2.
  • Practice problems: Chapter Two, III.2: 25, 26, 33.

Friday: Row and column spaces. (lecture, tex file, slides).
Week 5: September 27 - October 1
Monday: Linear transformations. (lecture, tex file, slides).
  • Reading: Chapter Three, II.1.
  • Practice problems: Chapter Three, Section II: 1.19, 1.20, 1.25, 1.28, 1.34, 1.36.

Tuesday: Turn in Week 5 Tuesday (overleaf template).
Wednesday: Range and nullspace. (lecture, tex file, slides).
  • Reading: Chapter Three, I.1 and I.2; Chapter Three, II.2.
  • Practice problems: Chapter Three, Section II: 2.21, 2.23, 2.24, 2.26, 2.35, 2.37, 2.40.

Friday: Rank-nullity theorem; isomorphisms. (lecture, tex file, slides).
  • Reading: Chapter Three, I.1 and I.2; Chapter Three, II.2.
  • Practice problems: Chapter Three, Section I: 1.21, 1.23, 1.30, 1.37, 2.15, 2.19, 2.20.
  • Turn in Exam 1 redo (see the email message from Saturday, September 25 for instructions).
  • No homework due today. The homework that was scheduled to be turned in today has been postponed until next Tuesday: Week 6 Tuesday (overleaf template) homework.
Week 6: October 4 - 8
Monday: Matrices and linear transformations I. (lecture, tex file, slides).
  • Reading: Chapter Three, Sections III.1 and III.2.
  • Practice problems: Chapter Three, Section III: 1.16, 1.17, 1.21, 1.27, 2.12, 2.13, 2.15, 2.22.

Tuesday: Turn in Week 6 Tuesday (overleaf template).
Wednesday: Matrices and linear transformations II: rank. (lecture, tex file, slides).
  • Reading: Chapter Three, Section III.2.
  • Practice problems: Chapter Three, Section III: 2.22, 2.26, 2.29, 2.33.

Friday: Matrices and linear transformations III: composition. (lecture, tex file, slides).
  • Reading: Chapter Three, Sections IV.2 and IV.3.
  • Practice problems: Chapter Three, Section IV: 2.14, 2.17, 2.26, 2.33, 3.24.
  • Turn in: Week 6 Friday (overleaf template) homework.
Week 7: October 11 - 15
Monday: Matrix inversion. (lecture, tex file, slides).
  • Reading: Chapter 3, IV.4.
  • Practice problems: Chapter 3, IV.4: 15, 17, 18, 20, 22, 28, 33, 35.

Tuesday: Turn in: Week 7 Tuesday (overleaf template).
Wednesday: Change of basis. (lecture, tex file, slides).
  • Reading: Chapter Three, V.1 and V.2.
  • Practice problems: Chapter Three, V.1: 1.7, 1.9, 1.10; V.2: 2.16, 2.17.

Friday: Determinants. (lecture, tex file, slides).
Week 8: October 25 - 29
Monday: The determinant of the transpose. (lecture, tex file, slides).
  • Reading: Chapter Four, I.1 and I.2.
  • Practice problems: Chapter Four, I.1: 1.6, 1.7, 1.8, 1.9.

Tuesday: Turn in: Week 8 Tuesday (overleaf template).
Wednesday: Permutation expansion of the determinant. (lecture, tex file, slides).
  • Reading: Course lecture notes.
  • Practice problems: Chapter Four, I.3: 3.20, 3.21.

Friday: Laplace expansion. Existence and uniqueness of the determinant. (lecture, tex file, slides).
Week 9: November 1 - 5
Monday: The space of all \(k\)-dimensional subspaces of a vector space. Exam 2 distributed after class today (due on Wednesday).
  • Reading: None.
  • Practice problems: None.

Tuesday: No homework due today.
Wednesday: Determinants and volume. Exam 2 due before class today. (worksheet, tex file; lecture, tex file).
  • Reading: Chapter Four, Section II.1.
  • Practice problems: 1.9, 1.12, 1.16, 1.21, 1.27.

Friday: Eigenvectors and eigenvalues. (lecture, tex file, slides).
Week 10: November 8 - 12
Monday Diagonalization algorithm. (lecture, tex file, slides).
  • Reading: Chapter Five, II.3.
  • Practice problems: Chapter Five, II.3: 21, 22, 23.

Tuesday: Turn in: Week 10 Tuesday (overleaf template).
Wednesday Eigenspaces. (lecture, tex file, slides).
  • Reading: Chapter V, II.3.
  • Practice problems: Chapter V, II.3: 24, 25, 28, 29

Friday: Algebraic and geometric multiplicity. Jordan form. (lecture, tex file, slides).
Week 11: November 15 - 19
Monday Walks on graphs. (lecture, tex file, slides).
  • Reading: today's lecture notes.
  • Practice problems: None.

Tuesday: Turn in: Week 11 Tuesday (overleaf template).
Wednesday Inner product spaces. (lecture, tex file, slides).
  • Reading: today's lecture notes.
  • Practice problems: None.

Friday: Length, distance, components, projections, angles. (lecture, tex file, slides).
Week 12: November 22-26
Monday Gram-Schmidt. (lecture, tex file, slides).
  • Reading: today's lecture notes.
  • Practice problems: None.

Tuesday: Turn in: Week 12 Tuesday (overleaf template).
Wednesday Orthogonal complements and orthogonal projections. (lecture, tex file, slides).
  • Reading: today's lecture notes.
  • Practice problems: None.
  • Here is a nice webpage supplementing the last example in today's lecture.

Friday: Thanksgiving break. No class today.

Week 13: November 29 - December 3
Monday Systems of linear differential equations. (lecture, tex file, slides).
  • Reading: today's lecture notes.
  • Practice problems: None.

Tuesday: Turn in: Week 13 Tuesday (overleaf template).
Wednesday Cross products. (lecture, tex file, slides).
  • Reading: today's lecture notes.
  • Practice problems: None.

Friday: Spectral theorem. Note: We meet in Physics 240A today. (lecture, tex file, slides).
Week 14: December 6 - 8
Monday Presentations.
Tuesday: No homework due today.
Wednesday Presentations.
Friday: Reading period. No class today.

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