Better Algebra

Linear Algebra and Geometry Course

Linear Algebra and Geometry - a.y. 2024-2025

E3

Office Hours

By appointment only

ada.boralevi@polito.it

Instructors & Schedule:

Boralevi - Geometry Lectures
Tuesday 8:30-10am and Wednesday 11:30am-2:30pm room 3
Perracchione - Numerical Analysis Lectures
Friday 8:30-10am room 3
Gollinucci - Exercise Sessions
Monday 2:30-4pm team 1 room 14 and Monday 4-5:30pm team 2 room 16
Perracchione - Exercise Sessions
Monday 2:30-4pm team 1 room 14 and Monday 4-5:30pm team 2 room 16

Exercise Sessions:

Team 1
Monday 2:30-4pm at Room 14
Team 2
Monday 4-5:30pm at Room 16

Course Resources

Course Material

Slides (from class)Lecture notes

Suggested textbooks:

  • G. Strang, Introduction to Linear Algebra, Wellesley-Cambridge Press, 2016.
  • E. Carlini, LAG: the written exam, CLUT 2019.

Course Schedule

40 Lectures
TitleDateContentReferences
Lecture 1
Lecture
2/25

Matrices with real coefficients. Opposite and transpose of a matrix, properties. Square matrices: diagonal, triangular, symmetric, skew-symmetric. Linear algebra on a number field different from R.

1.1, 1.2
Lecture 2-3
Lecture
2/26

Matrix addition and scalar multiplication: definition and properties, examples. Product of matrices: definition and examples. Properties of the product of matrices. Invertible matrices and their properties: inverse of the transpose and the product, examples. Linear equations and linear systems. Matrices associated to a linear system and matrix form.

2.1, 2.2
Session on 3/3
Exercise
3/3

Exercise session with dr. Gollinucci: exercises and slides

Lecture 4
Lecture
3/4

Linear equations, linear systems, solutions, associated matrices, examples. Homogeneous and compatible systems. Elementary row operations, pivots, row-echelon form. Equivalent matrices and equivalent linear systems. Examples of Gauss reduction. Rank of a matrix.

3.1, 3.2
Lecture 5-6
Lecture
3/5

Rank of a matrix. Examples and exercises on row reduction and rank computation. Solving a linear system: equivalent systems have equivalent associated matrices, Rouché-Capelli theorem, examples. Matrix equations and solutions: computation of inverse matrix via row reduction. Invertible matrices have maximal rank. Row and column rank, rank of the transpose. Submatrices, definition and examples.

4.3
Lecture 7
Lecture
3/11

Determinants: submatrices, cofactors, examples. Determinant of the transpose matrix. Determinant and elementary row and column operations. Laplace expansion along rows and columns. Binet's theorem. Invertible matrices have nonzero determinant. Skew-symmetric odd size matrices have zero determinant.

6.1, 6.2
Lecture 8-9
Lecture
3/12

Adjugate and cofactor matrix, computation of the inverse matrix using the adjugate, examples. Geometric vectors: segments, applied vectors, direction, orientation and length of a vector. Parallel and coplanar vectors. Cartesian systems of coordinates. Operations on vectors: sum and difference of vectors, multiplication by a scalar, properties and geometric interpretations. Quizzes on matrices and linear systems ( quizzes file 1 without solutions ).

6.3
Session on 3/17
Exercise
3/17

Exercise session with dr. Gollinucci: exercises and slides

Lecture 10
Lecture
3/18

Normalization of a vector. Characterization of parallel and coplanar vectors through rank. Dot (scalar) product: definition, examples, properties. Dot product and angles: parallel and orthogonal vectors.

7.5
Lecture 11-12
Lecture
3/19

Chauchy-Schwartz and triangle inequality. Orthogonal projection. Examples and exercises. Cross (vector) product: definition, geometric interpretation, properties, examples. Cross product and area of a triangle. Mixed product and volume of a tetrahedron. Some exercises on vectors. Introduction to parametric and cartesian equations of lines and planes.

8.1, 8.2, 8.3
Lecture 13
Lecture
3/25

Parametric equations of lines and planes in space, examples. Relative position of two lines in space, examples.

9.1, 9.2
Lecture 14-15
Lecture
3/26

Cartesian equations of planes in space; switching from parametric to Cartesian equation and backwards. Relative position of two planes in space and Cartesian equations of lines; switching from parametric to Cartesian equation and backwards. Relative position of linear objects in the space: a line and a plane and 2 lines. Examples and exercises.

10.1, 10.2, 10.3
Session on 3/31
Exercise
3/31

Exercise session with dr. Gollinucci: exercises and slides

Lecture 16
Lecture
4/1

Exercises from worksheet 5. Distance of two sets, definition. Distance of a point from a plane, examples.

11.1, part of 11.2
Lecture 17-18
Lecture
4/2

Distance of a point from a line, distance of a plane from another plane and from a line, distance between two lines, examples. Quizzes on lines and planes and distances ( quizzes file 3 without solutions )

11.2, 11.3, 11.4
Lecture 19-20
Lecture
4/5

Vector spaces and subspaces: definition, properties, examples. Union and intersection of subspaces, sum of subspaces, examples. Linear combinations. (Online lesson, you can find the recording on the teaching portal.).

12.1, 12.2,12.3
Lecture 21-22
Lecture
4/9

Linear combinations, generators, finitely generated vector spaces: definitions and examples. Linearly dependent and independent vectors, examples. The discarding algorithm, examples. Bases and components with respect to a basis, examples.

13.1, 13.2
Session on 4/12
Exam
4/12

1st midterm

Session on 4/14
Exercise
4/14

Exercise session with dr. Gollinucci: exercises and slides

Lecture 23-24
Lecture
4/16

Extract a basis from a set of generators and complete a set of independent vectors to a basis. Number of vectors in a basis and dimension of a vector spaces, examples. Dimension of vector subspaces, examples. Grassmann formula, direct sum. Dimension and matrix rank: row and column space of a matrix.

14.2
Lecture
Holiday

Easter & Liberation day break 4/18-->4/25

Lecture 25
Exam
4/29

Linear maps: definition, examples, some properties. Definition of Kernel and Image.

16.1, 16.2
Lecture 26-27
Lecture
4/30

Linear maps: kernel and image. Linear maps K^n-->K^m and their associated matrices, kernel, image and rank. Isomorphisms, isomorphic vector spaces, invertible matrices, examples. Linear maps for finitely generated vector spaces, examples.

16.2, 16.3, 16.4
Session on 5/5
Exercise
5/5

Exercise session with dr. Gollinucci: exercises and slides

Lecture 28
Lecture
5/6

Linear maps for finitely generated vector spaces, matrix associated to a linear map: definition and examples. Dimension theorem: kernel, image and rank of the associated matrix.

17.1, 17.2
Lecture 29-30
Lecture
5/7

Matrix associated to the composition of linear maps and to the inverse. Endomorphisms. Matrix of change of basis, examples. Eigenvalues, eigenvectors, eigenspaces: definition. Quizzes on vector spaces and subspaces.

17.2, 17.3
Lecture 31
Lecture
5/13

Eigenvalues, eigenvectors, eigenspaces, characteristic polynomial: definition, properties, how to find them, examples.

18.1, 18.2
Lecture 32-33
Lecture
5/14

Algebraic and geometric multiplicity of eigenvalues. Diagonalizable matrices. Similar matrices. Symmetric matrices are diagonalizable. Cayley-Hamilton theorem and eigenvalues of nilpotent matrices. Examples and exercises on diagonalization.

19.1, 19.2, 19.3
Session on 5/19
Exercise
5/19

Exercise session with dr. Gollinucci: exercises and slides

Lecture 34
Lecture
5/20

Inner products: definition and examples. Cauchy-Schwartz inequality. Orthogonal and orthonormal sets and bases. Gram-Schmidt orthonormalization algorithm, introduction.

20.1, 20.2
Lecture 35-36
Lecture
5/21

Orthogonal and orthonormal sets and bases. Gram-Schmidt orthonormalization algorithm, examples. Special and non-special orthogonal matrices. Orthonormal diagonalization for symmetric matrices, examples. Quizzes on linear maps, associated matrices, diagonalization ( quizzes file 5 without solutions )

20.2, 20.3, 20.4
Lecture 37
Lecture
5/27

Orthogonal matrices and rotations. Quadratic forms and symmetric matrices, positive/negative definite/semidefinite, indefinite forms.

20.3
Lecture 38-39
Lecture
5/28

More on quadratic forms and their character of definition, with examples. Descartes' rule of signs. Conics in their canonical form: hyperbola, ellipse, parabola. Conics and rototranslations in the Euclidean plane. Reduction of a conic in its canonical form.

21.2
Lecture
Exercise

Exercise session with dr. Gollinucci: exercises and slides

Session on 5/31
Exam
5/31

2nd midterm

Lecture
Holiday

Republic day 6/2

Lecture 40
Lecture
6/3

Classification of degenerate and non-degenerate conics through their associated matrices, examples. Introduction to quadric surfaces. Spheres: introduction and definition.

23.2, 23.2
Lecture 41
Lecture
6/4

Spheres and circles in space: definitions and examples. Tangent plane and tangent lines to a sphere, intersection of two spheres, radical plane, examples.

24.1, 24.2, 24.3
Lecture
Exercise

Exercise session with dr. Gollinucci: exam simulation 3, slides

Lecture 42
Exam
6/6

Exam simulation 4

Simulation 4 (w/ solutions)