Math 2130
Linear Algebra


Fall 2019


Please see below for lecture summaries, homework and other study material.

Date Topics
Aug.26. Matrix encodings of linear systems. Elementary row operations on matrices.
Aug.28. Echelon form of matrices. Principles of row reduction to echelon form.
Homework 1 (due Fri. Sept.6.): 1.1: 4, 12, 18, 20, 24; 1.2: 2, 4, 10, 12, 14, 16.
Aug.30. From echelon forms to solution sets of linear systems. The row reduction algorithm.
Sep.02. Labor day; no class.
Sep.04. Practice problems on solving linear systems. Linear combinations of vectors.
Homework 2 (due Wed. Sep.11.): 1.3: 2, 6, 12, 18; 1.4: 2, 4, 6, 8, 10, 14, 18, 22.
Sep.06. Vector equations and matrix equations. Spans of vectors.
Sep.09. Geometry of vectors. Homogeneous vs. nonhomogeneous equations.
Sep.11. Linear indepedence of vectors.
Homework 3 (due Wed. Sep.18.): 1.5: 4, 6, 16, 22, 32; 1.7: 2, 4, 6, 8, 12, 20, 22, 32.
Sep.13. More on linear independence. Definition of linear maps.
Sep.16. The linearity property. Linear maps vs matrix multiplication.
Sep.18. Geometric linear maps on the plane.
Homework 4 (due Wed. Sep.25.): 1.8: 8, 12, 14, 16, 20; 1.9: 4, 6, 8, 14, 22, 38, 40.
Sep.20. Image, kernel, injectivity, and surjectivity of linear maps.
Review Problems for Chapter 1
Sep.23. Matrix operations: addition, scalar multiplication, and matrix multiplication.
Sep.25. Properties of matrix multiplication. Matrix transpose.
Homework 5 (do not hand in): 2.1: 2, 6, 7, 15, 16, 18, 19.
Sep.27. Definition and basic properties of matrix inverses.
Sep.30. Midterm I.
Oct.02. Characterization of invertible matrices. Algorithm for finding matrix inverses.
Homework 6 (due Wed. Oct.9.): 2.2: 4, 8, 32; 2.3: 6, 8; 2.8: 1, 2, 4, 7.
Oct.04. Subspaces of R^n.
Oct.07. Column spaces and null spaces of matrices. Images and kernels of linear maps.
Oct.09. Bases of subspaces of R^n.
Homework 7 (due Wed. Oct.16.): 2.8: 18, 19, 20; 2.9: 2, 4, 8, 10, 14.
Oct.11. Dimensions of vector spaces. The rank-nullity theorem.
Oct.14. Coordinate systems. Determinants and cofactor expansions.
Oct.16. Properties of determinants.
Homework 8 (due Wed. Oct.23.): 3.1: 2, 10, 12, 38; 3.2: 16, 18, 20, 22; 3.3: 20, 22.
Oct.18. Cramer's rule. Determinants and volume.
Oct.21. Definition and examples of abstract vector spaces. Spans and linear independence.
Oct.23. Subspaces. Linear maps and their kernels and images. Composing proofs.
Homework 9 (due Wed. Oct. 30.): 4.1: 6, 8, 12, 16, 18, 20; 4.2: 10, 12; 4.3: 4, 14, 20.
Oct.25. Bases and dimensions of abstract vector spaces.
Oct.28. Coordinate systems and coordinate mappings.
Oct.30. Row spaces of matrices. Equality of row rank and column rank.
Homework 10 (due Wed. Nov. 6.): 4.4: 10, 12, 14; 4.5: 8, 10; 4.6: 4, 6, 8, 10; 4.7: 2, 4, 8.
Review Problems for Chapters 2-4 (solution guide)
Nov.01. Change of basis.
Nov.04. The matrix of a linear map (relative to chosen bases).
Nov.06. Eigenvectors, eigenvalues.
Homework 11 (do not hand in): 5.1: 2, 3, 5, 6, 9, 10, 18; 5.2: 1, 2.
Nov.08. Eigenspaces as kernels. Finding eigenspaces.
Nov.11. Midterm II.
Nov.13. Characteristic polynomials. Finding eigenvalues.
Homework 12 (due Wed. Nov. 20.): 5.1: 1, 8, 11, 12, 14; 5.2: 4, 6, 10, 16; 5.3: 2, 4, 7, 8.
Nov.15. Algebraic multiplicity vs. geometric multiplicitiy of eigenvalues. Diagonalizability.
Nov.18. Diagonalization problems.
Nov.20. More diagonalization problems. Matrices of linear maps and diagonalization.
Homework 13 (due Wed. Dec. 4.): 5.3: 10, 12, 14; 5.4: 2, 10, 14, 16, 18.
Nov.22. Diagonalization problems.
Dec.02. Inner products. Vector length via inner products.
Dec.04. Distance and orthogonality via inner products. Orthogonal sets.
Homework 14 (due Wed. Dec. 11.): 6.1: 4, 10, 12, 14; 6.2: 2, 8, 10, 12, 14; 6.3: 2, 8, 12, 14.
Dec.06. Orthogonal projections. Review Problems for Chapters 5-6
Dec.09. The Gram-Schmidt process.
Dec.11. Review for final exam.