Linear Algebra

Learn Linear algebra

Vectors, matrices, and transformations: the math of geometry in any dimension.

Free to start · adaptive placement finds your level · reviews timed to your own forgetting.

46 lessons in Linear algebra

What a vector isMatrices: grids of numbersVectors in ℝⁿA matrix times a vectorSystems & matricesMatrix multiplication & inversesLU decompositionDeterminantsSpan, linear independence & basisVector spaces & subspacesRank & null spaceThe four fundamental subspacesLinear transformationsThe invertible matrix theoremEigenvalues & eigenvectorsChange of basis & similarityDiagonalizationInner products & orthogonalityGram-Schmidt orthogonalizationCauchy-Schwarz inequalitySymmetric matrices & spectral theoremQR decompositionQuadratic formsSingular value decomposition (intro)Proof of rank-nullitySpectral theorem proofJordan canonical formCayley-Hamilton theoremMinimal polynomial & rational canonical formBilinear forms, signature & Sylvester's law of inertiaPositive-definite matrices & CholeskyDual spaces & bilinear formsNormal & unitary operators; Schur decompositionThe Moore–Penrose pseudoinverseBlock matrices & the Schur complementThe matrix exponentialMatrix & operator normsThe Perron–Frobenius theoremKronecker product & vectorizationCirculant & Toeplitz matricesSpectral graph theoryFunctions of matricesThe generalized eigenvalue problemTensor products & multilinear mapsMatrix Lie groups & Lie algebrasExterior algebra & the wedge product

Built to be understood — and remembered.

Every idea is taught with motivation and a worked example before the drills, and an FSRS spaced-repetition engine schedules each review for the day its model predicts you would forget it. A short placement check finds what you already know, so you start Linear algebra exactly where it's useful.