SME
College · Math
Linear Algebra
7 topics
Before this course
Topics
Row reduction
Main lesson
The inverse by row reduction
Use this for “Reduce [A | I] to find A⁻¹ for A = [[2, 1, 0], [1, 1, 0], [0, 0, 3]].”
LU factorization
Use this for “Factor A = [[2, 1, 1], [4, 3, 3], [8, 7, 9]] as A = LU.”
Echelon and reduced echelon form
Use this for “Is [[1, 3, 4], [0, 1, 2]] in echelon form, reduced echelon form, or neither?”
Vector spaces and subspaces
Main lesson
Are three vectors independent?
Use this for “Are ⟨1, 0, 1⟩, ⟨2, 1, 0⟩ and ⟨0, 1, 1⟩ linearly independent?”
Coordinates in a basis
Use this for “Find the coordinates of x = ⟨5, 1⟩ in the basis b₁ = ⟨1, 1⟩, b₂ = ⟨1, −1⟩.”
Is it a subspace?
Use this for “Is the set of points with y = 3x − 2 a subspace of ℝ²?”
Determinants
Eigenvalues and eigenvectors
Main lesson
An eigenvector of a 3 × 3 matrix
Use this for “λ = 3 is an eigenvalue of [[2, 0, 0], [1, 3, 0], [0, 1, 1]]. Find an eigenvector for it.”
Powers of a matrix by its eigenvectors
Use this for “A = [[4, 1], [2, 3]] and x = (1, 0). Find A³x by writing x in the eigenvectors of A.”
The steady state of a Markov chain
Use this for “Each year 10% of city dwellers move to the suburbs and 30% of suburb dwellers move to the city. What share lives in each in the long run?”
Complex eigenvalues: a turn and a stretch
Use this for “Find the eigenvalues of [[1, −1], [1, 1]] and the angle and scale factor of the map.”
Orthogonality and least squares
Linear transformations, kernel and range, change of basis
Main lesson
Kernel and range of a transformation
Use this for “T(x) = Ax with A = [[1, 2, −1], [2, 4, 1], [3, 6, 0]]. Find the kernel and the range of T. Is T one-to-one? Onto?”
A rotation then a reflection
Use this for “Rotate (3, 1) by 90° and then reflect it in the x-axis. Find the image and the one matrix that does both.”
Symmetric matrices, quadratic forms and the SVD
Course test
See what you know: 10 questions on this course
New questions each time. Pass to mark it complete.