Schedule

Notes

  • The schedule is tentative and will change as the course progresses.

  • For information about add/drop dates and other matters related to course registration, please consult the Registrar's Website.

  • All dates and times are in ET (Eastern Time).

  • Section numbers are as in Linear Algebra, Ideas and Applications (4th Edition) by Richard C. Penney.

  • There will usually be one homework assignment due on Saturday every week.

Week of January 13th (Week 1)

  • Classes begin on Tuesday, January 14th.

Tuesday, January 14th

  • Topics: Course logistics; systems of linear equations; geometry and size of the solution set; (in)consistent systems; parametric form; the augmented and coefficient matrices; elementary row operations; equivalent systems.

  • Reading: §1.2 Systems; §1.3 Gaussian Elimination.

  • Videos:

Thursday, January 16th

  • Topics: Elementary row operations (contd); equivalent systems (contd); echelon form; Gaussian elimination; reduced-row echelon form; pivots and rank; cases for the solution set.

  • Reading: §1.3 Gaussian Elimination.

  • Videos:

Week of January 20th (Week 2)

  • HW 1 is due on Saturday, January 25th at 11 PM.

Tuesday, January 21st

  • Topics: The space \(M_{m\times n}\); matrix arithmetic (addition, subtraction, scalar multiplication); the vector space \(\mathbb{R}^n\); abstract vector spaces; the spaces \(P(\mathbb{R})\) and \(P_n(\mathbb{R})\).

  • Reading: §1.1 The Vector Space of \(m\times n\) Matrices.

  • Videos:

Thursday, January 23rd

  • Topics: The function spaces (\(\mathcal{F}\), \(\mathcal{C}\), \(\mathcal{D}\)); linear combinations; linear (in)dependence; formally checking if \(v \in \mathrm{Span}\{v_1,\cdots,v_k\}\) by solving a linear system.

  • Reading: §1.3 Gaussian Elimination.

  • Videos:

Week of January 27th (Week 3)

  • I will be out of town this week; please see below for necessary adjustments.

  • HW 2 is due on Wednesday, February 5th at 11 PM (note: unusual day!).

  • No Office Hours this week (in view of my travel).

Tuesday, January 28th

  • No Class (compensation for evening exam).

Thursday, January 30th

  • Online Class (via Zoom).

  • Topics: Linear independence (contd); span; geometric aspects of independence and span in \(\mathbb{R}^n\).

  • Reading: §1.2 Systems; §2.1 The Test for Linear Independence.

  • Notes: (Morning, Evening)

  • Video:

Week of February 3rd (Week 4)

  • HW 2 is due on Wednesday, February 5th at 11 PM (note: unusual day!).

  • HW 3 is due on Saturday, February 8th at 11 PM.

Tuesday, February 4th

  • Topics: Testing if a set is linearly independent; pivot vectors and columns; the connection between linear (in)dependence in \(\mathbb{R}^m\) and pivot vectors; transpose and symmetric matrices.

  • Reading: §1.2 Systems; §2.1 The Test for Linear Independence.

  • Video:

  • Note: Due to a technical issue with the webcam, the Morning06 recording only begins halfway through class. I recommend watching the Afternoon06 recording instead.

Thursday, February 6th

  • Topics: Review of span; subspaces; multiplying an \(m\times n\) matrix with a vector in \(\mathbb{R}^n\); the equivalence between \(b\in \mathrm{Span}\{a_1,\cdots,a_n\}\) and solving the system \([ a_1 \cdots a_n | b]\); span as a subspace; the column space and row space of a matrix.

  • Reading: §1.4 Column Space and Nullspace; §2.1 The Test for Linear Independence.

  • Video:

Week of February 10th (Week 5)

  • HW 4 is due on Saturday, February 15th at 11 PM.

Tuesday, February 11th

  • Topics: The nullspace of a matrix; the linearity of matrix multiplication; describing \(\textrm{Null}(A)\) as a span; the translation theorem.

  • Reading: §1.4 Column Space and Nullspace; §2.1 The Test for Linear Independence.

  • Video:

Thursday, February 13th

  • Topics: Equivalent characterizations of subspaces; basis; standard bases of \(\mathbb{R}^n\), \(P_n(\mathbb{R})\), and \(M_{m\times n}(\mathbb{R})\); Computing bases of column spaces; computing bases of subspaces of \(\mathbb{R}^n\); linear relations between columns of a matrix are preserved under EROs; intuitive notion of dimension; formal definition of dimension; \(\dim V = |\mathcal{B}|\) where \(\mathcal{B}\) is any basis of \(V\).

  • Reading: §2.2 Dimension.

  • Video:

  • Note: Due to a technical issue, the Morning09 lecture was not recorded. Please watch the Afternoon09 lecture.

Week of February 17th (Week 6)

  • HW 5 is due on Saturday, February 22nd at 11 PM.

Tuesday, February 18th

  • Topics: Review of computing bases of column spaces and nullspaces; computing bases of row spaces; \(A\) and \(B\) are row-equivalent implies they have the same row space; proof of \(\dim V = |\mathcal{B}|\) where \(\mathcal{B}\) is any basis of \(V\); finite dimensional vector spaces; \(\mathbb{R}^\infty\) as an example of an infinite dimensional vector space.

  • Reading: §2.2 Dimension; §2.3 Row Space and the rank-nullity theorem.

  • Video:

Thursday, February 20th

  • Topics: Any two of \(|S| = \dim V\), \(S\) is spanning, and \(S\) is linearly independent implies the third; rank as dimension; row-rank = column-rank; column space as image of a matrix map; solvability of \(A\vec{x} = \vec{b}\) for every \(\vec{b} \in \mathbb{R}^m\) in terms of rank; nullity; nullity as a measure of size of the solution set of \(A\vec{x} = \vec{b}\); the rank-nullity theorem; implications of the rank-nullity theorem; nonsingular matrices; properties of nonsingular matrices.

  • Reading: §2.3 Row Space and the rank-nullity theorem.

  • Video:

Week of February 24th (Week 7)

  • Midterm 1 is on Thursday, February 27th from 8:00 PM to 9:00 PM in BHEE 170.

  • HW 6 is due on Wednesday, March 5th at 11 PM (note: non-standard day!).

  • In view of Midterm 1, Office Hours will be on T, 2:00 PM to 4:00 PM and Th, 3:30 to 4:30 PM this week.

Tuesday, February 25th

Thursday, February 27th

  • Topics: The product \(A \vec{x}\) as matrix multiplication; the index formula for matrix multiplication; the identity matrix; the matrix product \(AB\) when \(B\) is a collection of columns; the matrix product \(AB\) when \(A\) is a collection of rows; the transpose of a product; algebraic properties of matrix multiplication; invertible matrices; the inverse of a matrix; the equivalence between invertibility, nonsingularity, and full-rank; the inverse of a \(2 \times 2\) matrix.

  • Reading: §3.2 Matrix Multiplication (Composition); §3.3 Inverses.

  • Video:

Week of March 3rd (Week 8)

  • HW 6 is due on Wednesday, March 5th at 11 PM (note: non-standard day!).

  • HW 7 is due on Friday, March 14th at 11 PM (note: non-standard day!).

Tuesday, March 4th

  • Topics: The algorithm for computing inverses using EROs; proof of correctness of the algorithm; the uniqueness of inverses; the inverse of the transpose is the transpose of the inverse; the inverse of a product; the rank of \(AB\) is at most the rank of \(A\) (resp. \(B\)); transformations; the identity transformation; matrix transformations.

  • Reading: §3.1 The Linearity Properties; §3.2 Matrix Multiplication (Composition); §3.3 Inverses.

  • Video:

Thursday, March 6th

  • Topics: Rotations in \(\mathbb{R}^2\) as a matrix transformation; domain and codomain; equality of transformations; linear transformations; examples of linear transformations; matrix transformations as linear transformations; every linear transformation of Euclidean spaces is a matrix transformation; formula for the matrix of a linear transformation; image of a set under a transformation; the image of a line segment under a linear transformation; differentiation and integration as linear maps between function spaces.

  • Reading: §3.1 The Linearity Properties; §3.5 The Matrix of a Linear Transformation.

  • Video:

Week of March 10th (Week 9)

  • HW 7 is due on Friday, March 14th at 11 PM (note: non-standard day!).

  • Office Hours will be on Th, 3:30 PM to 6:30 PM this week (no office hours on Tuesday).

Tuesday, March 11th

  • Topics: Composition of transformations; composition of linear transformations; matrix multiplication as composition of linear transformations between Euclidean spaces; the identity matrix \(I_n\) as the identity transformation of \(\mathbb{R}^n\); invertible transformations; the inverse of a transformation; the inverse of a linear transformation is linear; the connection between the inverse matrix and the inverse of a linear transformation.

  • Reading: §3.1 The Linearity Properties; §3.3 Inverses; §3.5 The Matrix of a Linear Transformation.

  • Video:

Thursday, March 13th

  • Topics: Injective (one-one) transformations; surjective (onto) transformations; bijective transformations; the kernel of a linear transformation; characterization of injectivity in terms of kernel; characterization of surjectivity in terms of image; isomorphism; ordered bases; uniqueness of representations in an ordered basis \(\mathcal{B}\); the coordinate vector \([\vec{x}]_{\mathcal{B}}\); Cartesian coordinates as the coordinates with respect to the standard basis; the geometric interpretation of a coordinate system in \(\mathbb{R}^2\); the coordinate transformation \(C_{\mathcal{B}}\).

  • Reading: §3.5 The Matrix of a Linear Transformation.

  • Video:

Week of March 17th (Week 10)

  • No HW due this week (in view of Spring Break).

Tuesday, March 18th

  • No Class (Spring Break).

Thursday, March 20th

  • No Class (Spring Break).

Week of March 24th (Week 11)

  • HW 8 and HW 9 are due on Wednesday, April 2nd at 11 PM (note: unusual day!).

  • Office Hours will be on T, 2:00 PM to 3:30 PM this week (no office hours on Thursday).

Tuesday, March 25th

  • Topics: The coordinate vector \([\vec{x}]_{\mathcal{B}}\) (contd); \(P_{\mathcal{B}}\) and \(C_{\mathcal{B}}\); \(P_{\mathcal{B}}^{-1} = C_{\mathcal{B}}\); the point transformation and the coordinate transformation are isomorphisms; the matrix of a linear transformation of general vector spaces; change of basis formula for linear transformations of Euclidean spaces; a motivating example for change of basis; determinants as a criterion for invertibility.

  • Reading: §3.5 The Matrix of a Linear Transformation; §4.1 Definition of Determinant.

  • Video:

Thursday, March 27th

  • Topics: Minors and cofactors; the recursive definition of determinants; examples of using the definition to compute determinants; properties of determinants; \(\det A = \det A^{T}\); the action of row interchange or row scaling on determinants; additivity of determinants; multilinearity of the determinant; cofactor expansions along arbitrary rows or columns; sufficient conditions for \(\det A = 0\); the action of row addition on determinants; using EROs to compute determinants; upper and lower triangular matrices.

  • Reading: §4.1 Definition of Determinant; §4.2 Reduction and Determinant; §4.3 Inverses.

  • Video:

Week of March 31st (Week 12)

  • HW 8 and HW 9 are due on Wednesday, April 2nd at 11 PM (note: unusual day!).

  • HW 10 is due on Saturday, April 5th at 11 PM.

  • Extra Office Hours at M, 3:30 PM to 5:00 PM this week (in addition to usual Office Hours) in view of the postponed homework.

Tuesday, April 1st

  • Topics: The determinant of a triangular matrix; row equivalence and determinant; the determinants of RREF matrices; the connection between determinant, rank, and invertibility; Cramer's rule; the adjugate or adjoint of a matrix; formula for the inverse in terms of adjugates and determinants; uniqueness of the determinant as an alternating multilinear form; \(\det(AB) = (\det A)(\det B)\); the geometric interpretation of determinant.

  • Reading: §4.2 Reduction and Determinant; §4.3 Inverses.

  • Video:

Thursday, April 3rd

  • Topics: The geometric interpretation of determinant; the determinant as the scaling factor of a transformation on areas & volumes; eigenvectors and eigenvalues; using eigenvectors and basis change to compute \(A^k \vec{v}\) for large \(k\); the characteristic polynomial \(\det(A-\lambda I)\) of a matrix; computing eigenvalues; computing eigenvectors; eigenspaces.

  • Reading: §4.1 Definition of Determinant; §5.1 Eigenvectors.

  • Video:

Week of April 7th (Week 13)

  • Midterm 2 is on Wednesday, April 9th from 8:00 PM to 9:00 PM in BHEE 170.

  • HW 11 is due on Saturday, April 12th at 11 PM.

Tuesday, April 8th

  • Review for Midterm 2.

  • Topics: Computing eigenvalues and eigenspaces (contd).

  • Reading: §5.1 Eigenvectors; §5.2 Diagonalization.

  • Files: (Sample Midterm)

  • Video:

Thursday, April 10th

  • Topics: Issues relating to nonexistence of eigenvalues or eigenvectors; algebraic multiplicity \(n_j\) and geometric multiplicity \(m_j\) of an eigenvalue \(\lambda_j\); diagonalizable and nondiagonalizable matrices; diagonalization; diagonalization as a change of basis; eigenvectors of distinct eigenvalues are linearly independent; a matrix with no real eigenvalues; the complex numbers, \(\mathbb{C}\); arithmetic in \(\mathbb{C}\); the Argand plane; polar coordinates for the Argand plane; change of variable formulae for polar to rectangular and vice-versa; modulus and argument of a complex number; the geometric interpretations of addition and multiplication.

  • Reading: §5.2 Diagonalization; §5.3 Complex eigenvectors.

  • Video:

Week of April 14th (Week 14)

  • I will be out of town for part of this week; please see below for necessary adjustments.

  • Office Hours will be on Th, 2:00 PM to 5:00 PM this week (no office hours on Tuesday).

  • HW 12 is due on Saturday, April 19th at 11 PM.

Tuesday, April 15th

  • No Class (compensation for evening exam).

Thursday, April 17th

  • Reading: §5.3 Complex eigenvectors; §3.4 The \(LU\) factorization.

Week of April 21st (Week 15)

  • HW 13 is due on Saturday, April 26th at 11 PM.

Tuesday, April 22nd

  • Reading: §5.2 Diagonalization; §5.3 Complex eigenvectors; Lecture Notes.

Thursday, April 24th

  • Reading: §5.2.2 Applications to Systems of Differential Equations; §6 Orthogonality.

Week of April 28th (Week 16)

  • No HW due this week (in view of Quiet Period).

  • Extra Office Hours at F, 2:00 PM to 4:00 PM this week (in addition to usual Office Hours) in view of the final exam.

Tuesday, April 29th

  • Review for Final Exam.

Thursday, May 1st

  • Review for Final Exam.

Week of May 5th (Final Exam Week)

  • Final Exam is on Monday, May 5th from 1:00 PM to 3:00 PM.