Week Date Contents
1 0514
First lecture
outline: course homepage, textbook, grading, homework and exam policies
The rest of the lecture was cancelled due to a power disruption
0516
§1.1 Systems of linear equations
definitions, Ex 1: a system of 2 equations of 2 unknowns; geometric interpretation, possibilities of the solution set. Matrix notation, Ex 2: redo Ex 1 in matrix form.
0517 elementary row operations, Ex 3, forward and backward phases, Ex 4 and Ex 5
§1.2 Row reduction and echelon forms
definitions of echelon form and reduced echelon form, pivot position and pivot column, Ex 1, 2; Finding general solution from reduced echelon form, Ex 2 again, Deciding existence and uniqueness from echelon form.
0518 Ex 3
§1.3 Vector equations
vectors, sum and scalar multiple, Ex 1, geometric meaning in R^2, linear combinations, Ex 2, 3 and 4, equivalence of being a linear combination and the linear system, Span, Ex 5, 6.
§1.4 Matrix equations
product of a matrix and a vector, Ex 1 and 2. Equivalence of a matrix equation, a vector equation and a linear system, Ex 3. When does a matrix equation Ax=b has a solution for a given b? Ex 4. When does a matrix equation Ax=b has a solution for every b?
2 0521
Victoria Day
0523
H1 due
Ex 5. Properties and computation of Ax, Ex 6
§1.5 Solution sets of linear systems
solution sets of homogeneous systems, Ex 1, 2, 3
0524 Ex 3 solution 2, the solution set of a homogeneous system is a span. Nonhomogeneous system, Ex 4 and 5, properties of the solution set of a nonhomogeneous system, geometric meaning.
(We skip §1.6)
§1.7 Linear independence
definition, Ex 1, 2, special cases, Ex 1 again, Ex 3, equivalence of linear dependence and existence of redundant vector, Ex 2 again, Ex 4, p>m implies linear dependence, Ex 5
§1.8 Linear transformations
terminologies, matrix transformations, Ex 1
0525 Ex 2-4, Ex 5 on gemetric meaning of 2x2 matrix transformations. Linear transformations, definition and properties, Ex 6-9.
§1.9 the matrix of a linear transformation
standard basis, the theorem that any linear transformation from R^n to R^m is a matrix transformation, Ex 1-3
3 0528
Ex 4-5, definition and theorem of onto and one-to-one linear transformations, Ex 6.
§2.1 Matrix operations
sum and scalar multiplication of matrices, Ex 1, composition of linear transformations, definition and formula of matrix multiplication, Ex 2, 3, computation rule, Ex 3 again, properties of matrix multiplication, Ex 4. Powers of a square matrix, Ex 5, 6.
0530
Midterm exam 1
0531 transpose, Ex 7, 8, 9
§2.2 The inverse of a square matrix
definition of invertible/inverse. Inverse is unique. Formula of the inverse matrix when n=2. Ex 1. Application for solving linear system, Ex 2. Properties of inverse matrix, Ex 3. Algorithm using row reduction, Ex 4 and 5. Right and left inverse for non-square matrices, Ex 6**.
0601 §2.3 Characterization of inverse matrices
Invertible Matrix Theorem: on equivalent statements for invertible square matrices, Ex 1 and 2**, geometric meaning.
Note: The exams will not include elementary matrices, right and left inverses. We also skip 2.4
§2.5 Subspaces of R^n
definition of subspaces, Ex 1, 2, 3. Column and null spaces of a matrix, Ex 4. Spanning set and basis. Ex 5--8.
4 0604
The theorem that pivot columns form a basis of the column space. Ex 9.
§2.6 Dimension and rank
Coordinate vector, Ex 1. Dimension theorem and definition, Ex 2. Ex 3. Rank. The rank theorem. Ex 4. The basis theorem. Extension of the Invertible Matrix Theorem.
§3.1 Introduction to determinants
Determiniant of a 3x3 matrix, Ex 1. Cofactor. Determiniant of an nxn matrix. The theorem on cofactor expansion. Ex 1 again, Ex 2. determinant of a triangular matrix, Ex 3. Ex 4.
0606
H2 due
§3.2 Properties of determinants
theorem on the change of the determinant under row/column operations, proof for 2x2 matrices, Ex 1--4. A square matrix A is invertible iff det A is nonzero. Ex 5. det A^T = det A. det(AB) = det A . det B.
0607 Ex 6, determinant as a ratio of volumes (not in exam).
§4.1 Eigenvectors and eigenvalues
Ex 1, definition, Ex 2-4. Eigenvalues of triangular matrices, Ex 5. Eigenvectors with distinct eigenvalues are linearly independent
§4.2 The characteristic equation
The characteristic equation, Ex 1, Ex 2
0608 Ex 3, algebraic and geometric multiplicity, Ex 4-5, characteristic eq for triangular matrices. Discrete dynamical systems, Ex 6 (population dynamics), Ex 7 (Fibonacci's rabbits)
5 0611
Similarity, similar matrices have the same determinants, characteristic polynomials, eigenvalues, algebraic and geometric multiplicities of eigenvalues, Ex 8-9. A matrix with no real eigenvalue, Ex 10.
§4.3 Diagonalization
Ex 1, 2. Diagonalizable matrix. An nxn matrix is diagonalizable if and only if it has n linearly independent eigenvectors. Ex 3-7. Special case when all eigenvalues are distinct. Ex 8. Ex 9. General case: An nxn matrix is diagonalizable if and only if the sum of geometric multiplicities is n.
0613
Midterm exam 2
0614 §4.4 Eigenvectors and linear transformations
Matrix of a linear transformation in R^n relative to a basis, Ex 1-4.
(We do not consider general linear transformations between vector spaces.)
§4.5 Complex eigenvalues
Complex numbers, Ex 1-2, Theorem of De Moivre, Ex 3.
Link to Appendix B on complex numbers.
0615 Complex eigenvalues, Ex 4-7, conjugate eigenvalue, A=PCP^{-1} with C = [[a,b]^T, [-b, a]^T]
§4.6 skipped
(It contains more advanced topics in discrete dynamical systems, including graphics and those with complex eigenvalues. However, the limit behavior of the simple discrete dynamical systems studied in §4.2 will be in final exam.)
§5.1 Inner product, length, and orthogonality
dot product, Ex 1, length, Ex 2-3, distance, Ex 4, orthogonality, Ex 5, orthogonal to a set, orthogonal complement, Ex 6. Theorem on orthogonal complement.
6 0618
H3 due
Ex 7, Ex 8, angles, Ex 9 (We skip Theorem 3)
§5.2 Orthogonal sets
orthogonal sets, Ex 1-2, an orthogonal set of nonzero vectors is linearly indepdent. Formula for coefficient. Ex 3. orthogonal projection onto a line, Ex 4-5
0620
Ex 6 matrix of a reflection. Orthonormal sets, Ex 7. Matrices with orthonormal columns, Ex 8. An mxn matrix U has orthonormal columns iff U^T U=I_n. In that case, U: R^n -> R^m preserves length and angle. Ex 9.
0621 last lecture
Orthogonal/orthonormal matrices, Ex 10 and remarks
§5.3 Orthogonal projections
Theorem 8 on orthogonal decomposition, Ex 1. Theorem 9 on best approximation, Ex 2. Projection to a plane with non-orthogonal basis, Ex 3, Ex 4.
Review of April 2017 final exam.
0622 no class