Visual Tools
Calculators
Tables
Mathematical Keyboard
Converters
Other Tools
Home › Linear Algebra
SECTIONLinear Algebra15 subsectionsBROWSE ALL ↓INTERACTIVE2 TOOLSLinear AlgebraVisual Tools48 toolsJump to ↓Linear AlgebraCalculators3 toolsJump to ↓fREFERENCE379 ITEMSfLinear AlgebraFormulas259 itemsJump to ↓AaLinear AlgebraTerms andDefinitions120 itemsJump to ↓§CORE TOPICS11 SUBSECTIONSMatrix decompositions5 TOPICSJump to ↓Row operations and thedeterminant4 TOPICSJump to ↓Eigenvalues and Eigenvectors4 TOPICSJump to ↓Solving A x = b4 TOPICSJump to ↓Matrices in Linear Algebra5 TOPICSJump to ↓Orthogonality in LinearAlgebra5 TOPICSJump to ↓Linear Transformations5 TOPICSJump to ↓[Foursubspaces](!/linear-algebra/vector-spaces/fundamental-spaces)7 TOPICSJump to ↓What Is a Vector6 TOPICSJump to ↓Interactive ToolsJump to ↓Linear Algebra SymbolsReferenceJump to ↓

Introduction to Linear Algebra

Linear algebra is a field of mathematics that focuses on studying vectors, matrices, and the relationships between them, forming the mathematical framework for analyzing structures and transformations in multidimensional spaces. It introduces powerful tools to understand and solve problems where quantities interact linearly, making it fundamental to numerous disciplines.

This field begins with vectors—quantities that have both magnitude and direction—and their operations, such as addition and scaling. It extends to matrices, which are grid-like arrangements of numbers used to represent systems of equations or transformations. Learning how to manipulate matrices and understand their properties is a key part of linear algebra.

Students also explore vector spaces, the environments in which vectors live, and subspaces, which reveal structure and constraints within these spaces. Concepts like linear independence, span, and basis give insight into how vectors relate and interact. The study of linear transformations, which describe how vectors change under operations like rotations or scaling, helps build a deeper understanding of the subject.

To help students navigate these foundational concepts, we created a dedicated Matrix Theory section that provides an in-depth exploration of matrices - from basic definitions and notations to various matrix types and properties. This interactive guide covers matrix structure, indexing, special cases of square matrices, and key matrix properties, with clear mathematical notation and visual examples throughout. The section serves as both a comprehensive learning resource and a quick reference for understanding these essential building blocks of linear algebra.

Eigenvalues and eigenvectors, pivotal concepts in linear algebra, allow students to uncover hidden properties of transformations. Techniques like solving systems of equations, matrix decomposition, and understanding projections or orthogonality are practical outcomes of this study.

Ultimately, linear algebra provides a foundation for solving abstract and applied problems, developing skills to think logically, recognize patterns, and simplify complex systems. It equips students with a versatile toolkit for further studies in mathematics, sciences, engineering, and beyond.

Linear Algebra Visual Tools

48 toolsExplore Linear Algebra Visual Tools →
Each tool turns a piece of linear algebra into something you can manipulate, watch, and step through — matrix operations, row reduction, vector geometry, systems of equations, and more.
×=row × column
Visual Tool

Key Terms

Open tool →
=ALLᵀ√ on the diagonal
Visual Tool

Cholesky Decomposition Visualizer

Watch A = L Lᵀ assemble for a symmetric positive definite matrix of your own numbers: each diagonal entry of L is a square root of what is left of the matching entry of A, each entry below it is a division, and the transpose fills in step on the right. Edits are mirrored to keep A symmetric, a shuffle produces guaranteed positive definite matrices, and two presets stop the run on purpose to show the unsymmetric and the indefinite cases.

Open tool →
λ = a ± bi
Visual Tool

Complex Eigenvalues 2D Visualizer

Drag a start vector and watch a real 2×2 matrix with complex eigenvalues turn it step by step: the orbit spirals in, spirals out, or runs round an ellipse, and a continuous spiral traces A^k x₀ between the steps. The matrix card shows the rotation-scaling form A = P C P⁻¹ with the real and imaginary parts of a complex eigenvector as the columns of P, and the live card reads r from the determinant and θ from the trace. Seven presets from plain rotations to skewed spirals, editable entries, and a real-eigenvalue fallback.

Open tool →
AᵀA x̂ = Aᵀb
Visual Tool

Least Squares Visualizer

Solve a least-squares problem with your own numbers exactly as it is done by hand: row reduce [A | b] to see that no exact solution exists, form the normal equations AᵀA x̂ = Aᵀb as matrix products, solve them, compute the projection p = A x̂, check that the residual b − p is perpendicular to every column, and build the projection matrix A(AᵀA)⁻¹Aᵀ. For design matrices the captions read off the fitted line or parabola and its errors. Presets include projection onto a line and a plane, a consistent system, and dependent columns.

Open tool →
111onenonemany[A | b] → rref
Visual Tool

Linear System Solutions Visualizer

Row reduce a system of your own numbers all the way to reduced row echelon form, one operation per scene, and read the solution set from the result: the solution vector when every column has a pivot, the row 0 = c that proves there is none, or a particular solution plus one direction per free variable when there are infinitely many. Six presets cover the three outcomes, a homogeneous system, an overdetermined but consistent one, and a plane of solutions with two free variables.

Open tool →
T(x) = Ax
Visual Tool

Linear Transformation 2D Visualizer

Drag the t slider to morph the identity matrix continuously into any 2x2 matrix A and watch the plane reshape. The unit square fills with color to show orientation, eigenvectors highlight as magenta lines, kernel and image lines appear when A is singular, and a live readout tracks determinant, trace, eigenvalues, and rank across twelve preset scenarios.

Open tool →
|A|+ − +
Visual Tool

Determinant Visualizer

Watch a determinant assemble term by term for any square matrix from 2×2 to 5×5. Four strategies show the same number four ways: the diagonal product at 2×2, Sarrus

Open tool →
A=PP−1Aⁿ = P Dⁿ P⁻¹
Visual Tool

Matrix Diagonalization Visualizer

Diagonalize a matrix of your own numbers as A = P D P⁻¹, exactly as it is done by hand: the eigenvectors become the columns of P, the eigenvalues fill the diagonal of D, P is inverted by row reduction, and the product is multiplied out and checked. Then pick a power k and watch A^k drop out of P D^k P⁻¹. Presets include a Markov chain settling to its steady state, the Fibonacci matrix, a symmetric matrix with orthogonal eigenvectors, and a defective shear that cannot be diagonalized.

Open tool →
A-1adj A / det A
Visual Tool

Matrix Inverse Visualizer

Watch the inverse of a 2×2 or 3×3 matrix build by the adjugate formula — strike a row and a column for every entry to read off its cofactor, transpose the cofactor matrix into the adjugate, expand the determinant along the first row from cofactors already in hand, then divide every entry by it. Every cofactor is written out symbolically, and the page explains why the transpose is necessary and why a zero determinant stops the construction.

Open tool →
Visual Tool

Key Terms

Open tool →
×Av by columns
Visual Tool

Matrix Multiplication by Columns

Build a matrix times a vector the way the definition says, then watch the same products regroup into whole columns. Each entry of the vector becomes a weight on one column of the matrix, and each scaled column is drawn in the plane as an arrow laid tail to head on the one before it. A second tab repeats the argument with a matrix on the right, assembling the product one column at a time. The reading leads straight to span, column space, rank and the question of when a system can be solved.

Open tool →
×vᵀA by rows
Visual Tool

Matrix Multiplication by Rows

Put the vector on the left and the matrix hands over its rows. The tool fills the product one term at a time by the definition, then regroups the same terms across instead of down, so each entry of the vector becomes a weight on a whole row. Every scaled row is drawn in the plane, laid tail to head on the one before it. A second tab repeats the argument with a matrix on the left, building the product one row at a time. This is the reading behind elementary matrices, row equivalence and elimination.

Open tool →
AB, two ways
Visual Tool

Matrix Multiplication by Rows and Columns

One product, two decompositions, and the relationship between them. The tool builds AB a column at a time out of the columns of A, then a row at a time out of the rows of B, then puts a column and a row of the finished product in the same plane so you can see the single entry they share. Colour marks the role each factor plays rather than its name, so the swap between readings is visible as it happens. This page explains how the two readings fit together rather than teaching either one.

Open tool →
·→A²Aⁿ = A·A·⋯·A
Visual Tool

Matrix Power Visualizer

Watch n copies of a square matrix collapse pairwise into Aⁿ, one bracket-and-collapse per stage, with the exponent growing by one each time. Cells of A² are written out in full as sums of products; from A³ upward each cell shows a Σ summary, and hovering it lists every term with the count in the header. Sizes 2×2 to 4×4 and exponents up to 5, which is enough to see the term count double or triple at every collapse.

Open tool →
Visual Tool

Key Terms

Open tool →
111000000special matrices
Visual Tool

Square Matrix Types Generator

Generate a square matrix of any of the classic special types — identity, zero, scalar, diagonal, upper and lower triangular, symmetric, skew-symmetric, or random — at the size you choose, and see which entries are forced and which are free. Each type comes with a short explanation, its defining pattern in colour, and the properties that follow from it: what its determinant and eigenvalues look like, what it does under multiplication, and where it turns up in decompositions and physics.

Open tool →
QᵀQ = I
Visual Tool

Orthogonal Matrices Visualizer

Test a matrix of your own numbers for orthogonality exactly as it is done by hand: multiply QᵀQ and compare with the identity, read the determinant to separate rotations from reflections, watch lengths and dot products of a test vector survive, verify that the transpose is the inverse, and identify the transformation, as a rotation angle or mirror line in the plane or an axis and angle in space. Near misses are diagnosed: perpendicular columns of the wrong length are normalized on the spot. Presets include a permutation, a Householder reflection and a scaled rotation.

Open tool →
Visual Tool

Key Terms

Open tool →
vPvP² = P
Visual Tool

Projection 2D Visualizer

Drag a vector in the plane and watch its orthogonal projection slide along a line as the foot of the perpendicular, with the kernel line, the dropline and a right-angle mark drawn in. Morph the grid from the identity to the projection matrix to see the plane flatten onto the line, read the 2×2 matrix and its invariants live, and set the line by preset or by an angle slider. Seven presets cover the coordinate axes, the diagonals and custom angles.

Open tool →
Visual Tool

Key Terms

Open tool →
vRvR² = I
Visual Tool

Reflection 2D Visualizer

Drag a vector in the plane and watch its mirror image across a line through the origin, joined by a perpendicular whose midpoint is the projection onto the mirror. Morph the grid from the identity to the reflection and see it pass through the projection halfway, with the unit square flattening and then flipping colour as the determinant crosses from +1 to −1. Read the 2×2 matrix and its invariants live, and set the mirror by preset or angle slider.

Open tool →
A = UΣVᵀAvᵢ = σᵢuᵢ
Visual Tool

Singular Value Decomposition Visualizer

Compute the SVD of a matrix of your own numbers, of any shape from 2×2 to 3×3, exactly as it is done by hand: form AᵀA, take its eigenvalues and eigenvectors, set σᵢ = √λᵢ and uᵢ = A vᵢ / σᵢ, complete U when the rank falls short, and assemble A = U Σ Vᵀ with a rectangular Σ. The factorization is multiplied out and rewritten as a sum of rank-one terms, and the final scene reports the rank, the spectral and Frobenius norms, the condition number and the four fundamental subspaces. Presets include a rank-one matrix, a rotation with repeated singular values, and wide and tall rectangular cases.

Open tool →
abspan = ℝ²
Visual Tool

Span and Linear Independence 2D Visualizer

Drag two vectors in the plane and see their span directly: a filled parallelogram and a plane-covering lattice when they are independent, a collapsed segment and a single dashed line when one is a multiple of the other. Sweep one vector a full turn to watch the determinant trace a sine wave and cross zero at exactly the two dependent angles. Nine presets cover orthogonal, oblique, near-aligned, parallel, anti-parallel and zero-vector pairs, and a live card reports lengths, angle, determinant, area and rank.

Open tool →
ww = c₁v₁ + c₂v₂ ?
Visual Tool

Span and Membership Visualizer

Enter spanning vectors and a test vector in R² to R⁴ and settle three questions exactly as they are settled by hand: row reduce V to find the dimension of the span and any dependencies among the vectors, row reduce [V | w] to decide whether w is a combination of them, and read off and verify the coordinates when it is. Dependent sets are diagnosed with their relations, non-unique coordinates are explained, and a vector outside the span is reported with the rank it adds. Presets cover a plane, a line, a dependent set, a basis of R³ and a plane in R⁴.

Open tool →
Visual Tool

Key Terms

Open tool →
‖v‖v̂√(v₁² + v₂²)
Visual Tool

Vector Magnitude and Unit Vector Visualizer

Watch the magnitude of a vector build in three phases — square each component, sum the squares and take the root, then divide every component by that one number to get the unit vector. Choose magnitude only or magnitude followed by normalization, set the length from 1 to 6 components, and see why the direction survives normalization while the length becomes exactly 1.

Open tool →
uvᵀu vᵀ · rank 1
Visual Tool

Outer Product of Vectors Visualizer

Watch the outer product u vᵀ fill as a matrix — every entry of u against every entry of v — cell by cell, row by row, or column by column. Set the two lengths independently, from 1 to 5 each, and see why no matching rule applies, why every row is a copy of vᵀ and every column a copy of u, and why that makes the result a rank-1 matrix, the building block of matrix multiplication and the singular value decomposition.

Open tool →
Explore Linear Algebra Visual Tools →

Linear Algebra Formulas

259 itemsSee All Linear Algebra Formulas →
Navigate through an essential collection of linear algebra formulas that power mathematical analysis and transformations. This guide presents key formulas across vector operations, matrix calculations, eigenvalues, and linear transformations — each equipped with clear notation, detailed explanations, and practical examples. You will find precise mathematical representations, component breakdowns, and specific use cases for over 15 fundamental formula categories. The organized structure helps you quickly locate and understand the tools you need, whether for solving equations, analyzing transformations, or applying linear algebra concepts in real-world scenarios. Perfect for students needing formula clarification, researchers requiring quick mathematical reference, or practitioners applying linear algebra in their work.
View All Linear Algebra Formulas →

Linear Algebra Terms and Definitions

120 itemsSee All Linear Algebra Terms and Definitions →
Discover essential linear algebra definitions that form the mathematical foundation for understanding vectors, matrices, and their relationships. This guide breaks down key terms from basic vector concepts like magnitude and direction to advanced matrix classifications and properties. Each definition includes precise mathematical notation, clear explanations, and visual examples to help grasp the concept. Whether you’re learning about vector spaces, exploring matrix types like triangular and symmetric matrices, or studying transformations, this organized reference makes complex linear algebra terminology accessible. The page serves as both a learning tool and a quick reference for students and practitioners, featuring interactive mathematical notation and practical examples throughout.
Vectors18
VectorAn ordered list of nn real numbers: v=(v1,v2,…,vn)∈Rn\mathbf{v} = (v_1, v_2, \ldots, v_n) \in \mathbb{R}^nRead more →ScalarAn element of the underlying field — in standard linear algebra, a real number c∈Rc \in \mathbb{R}Read more →Magnitude (Norm)The length of a vector, measured as its distance from the origin:
∥v∥=v12+v22+⋯+vn2\|\mathbf{v}\| = \sqrt{v_1^2 + v_2^2 + \cdots + v_n^2}
Read more →
Unit VectorA vector u^\hat{\mathbf{u}} with ∥u^∥=1\|\hat{\mathbf{u}}\| = 1Read more →Dot ProductAn operation that takes two vectors and returns a scalar, computed by summing the products of corresponding components:
$$\mathbf{u} \cdot \mathbf{v}…
Read more →
Cross ProductA binary operation on two vectors in R3\mathbb{R}^3 that produces a vector perpendicular to both inputs:
$$\mathbf{u} \times \mathbf{v} =…
Read more →
Linear CombinationA sum of vectors, each multiplied by a scalar coefficient:
c1v1+c2v2+⋯+ckvkc_1\mathbf{v}_1 + c_2\mathbf{v}_2 + \cdots + c_k\mathbf{v}_k
Read more →
Zero VectorThe vector 0=(0,0,…,0)\mathbf{0} = (0, 0, \ldots, 0) whose every component is zeroRead more →DirectionThe orientation of a non-zero vector, captured by its unit vector v/∥v∥\mathbf{v} / \|\mathbf{v}\|Read more →Vector ProjectionThe component of u\mathbf{u} lying along v\mathbf{v}:
$$\text{proj}_{\mathbf{v}}\mathbf{u} = \frac{\mathbf{u} \cdot \mathbf{v}}{\mathbf{v} \cdot…
Read more →
Orthogonal DecompositionThe unique splitting of a vector into a part inside a subspace WW and a part in its orthogonal complement:
$$\mathbf{u} = \text{proj}_W\mathbf{u} +…
Read more →
Outer ProductThe matrix uvT\mathbf{u}\mathbf{v}^T with entries (uvT)ij=uivj(\mathbf{u}\mathbf{v}^T)_{ij} = u_i v_jRead more →Hadamard ProductThe entry-wise product of two same-shaped matrices: (A∘B)ij=aij bij(A \circ B)_{ij} = a_{ij}\,b_{ij}Read more →Frobenius Inner ProductThe inner product of two same-shaped matrices obtained by treating them as long vectors:
$$\langle A, B \rangle_F = \sum_{i,j} a_{ij}\,b_{ij} =…
Read more →
Frobenius NormThe length of a matrix measured as if its entries were one long vector:
∥A∥F=∑i,jaij2=tr(ATA)\|A\|_F = \sqrt{\sum_{i,j} a_{ij}^2} = \sqrt{\text{tr}(A^T A)}
Read more →
Inner Product SpaceA vector space equipped with an inner product ⟨⋅,⋅⟩\langle \cdot, \cdot \rangle that is symmetric, linear in each argument, and positive definiteRead more →Right-Hand RuleThe convention fixing the direction of a cross product u×v\mathbf{u} \times \mathbf{v}Read more →IsometryA linear transformation that preserves lengths: ∥Tv∥=∥v∥\|T\mathbf{v}\| = \|\mathbf{v}\| for every v\mathbf{v}Read more →
Vector SpaceA set VV equipped with vector addition and scalar multiplication satisfying the vector space axiomsRead more →SubspaceA nonempty subset W⊆VW \subseteq V that is itself a vector space under the same operationsRead more →SpanThe set of all linear combinations of a given collection of vectors:
$$\text{Span}\{\mathbf{v}_1, \ldots, \mathbf{v}_k\} = \{c_1\mathbf{v}_1 + \cdots…
Read more →
Linear IndependenceVectors v1,…,vk\mathbf{v}_1, \ldots, \mathbf{v}_k are linearly independent if the only solution to
$$c_1\mathbf{v}_1 + \cdots + c_k\mathbf{v}_k =…
Read more →
BasisA set {v1,…,vn}\{\mathbf{v}_1, \ldots, \mathbf{v}_n\} that is linearly independent and spans the entire vector spaceRead more →DimensionThe number of vectors in any basis of a vector space VV, denoted dim⁡(V)\dim(V)Read more →Column SpaceThe set of all vectors expressible as AxA\mathbf{x} — equivalently, the span of the columns of AA:
$$\text{Col}(A) = \{A\mathbf{x} \mid \mathbf{x}…
Read more →
Null Space (Kernel)The set of all solutions to the homogeneous system Ax=0A\mathbf{x} = \mathbf{0}:
$$\text{Nul}(A) = \{\mathbf{x} \in \mathbb{R}^n \mid A\mathbf{x} =…
Read more →
Row SpaceThe span of the rows of a matrix, equivalently the column space of its transpose:
Row(A)=Col(AT)\text{Row}(A) = \text{Col}(A^T)
Read more →
Left Null SpaceThe null space of the transpose ATA^T — the set of all vectors y\mathbf{y} satisfying ATy=0A^T\mathbf{y} = \mathbf{0}:
$$\text{Nul}(A^T) = \{\mathbf{y}…
Read more →
CoordinatesThe unique scalars c1,…,cnc_1, \ldots, c_n expressing a vector in a chosen basis:
$$\mathbf{v} = c_1\mathbf{b}_1 + c_2\mathbf{b}_2 + \cdots +…
Read more →
Pivot ColumnA column of a matrix that contains a pivot after row reductionRead more →Free VariableA variable whose column carries no pivot after row reductionRead more →Special SolutionsThe solutions of Ax=0A\mathbf{x} = \mathbf{0} obtained by setting one free variable to 11 and the others to 00Read more →NullityThe dimension of the null space: nullity(A)=n−rank(A)\text{nullity}(A) = n - \text{rank}(A)Read more →Rank-Nullity TheoremFor an m×nm \times n matrix: rank(A)+nullity(A)=n\text{rank}(A) + \text{nullity}(A) = nRead more →Full RankA matrix whose rank is as large as its shape allows: rank(A)=min⁡(m,n)\text{rank}(A) = \min(m, n)Read more →
MatrixA rectangular array of numbers with mm rows and nn columns: A∈Rm×nA \in \mathbb{R}^{m \times n}Read more →Square MatrixA matrix with equal numbers of rows and columns: A∈Rn×nA \in \mathbb{R}^{n \times n}Read more →Identity MatrixThe square matrix with 11s on the main diagonal and 00s elsewhere, denoted InI_n:
$$I_n = \begin{pmatrix} 1 & 0 & \cdots & 0 \\ 0 & 1 & \cdots & 0…
Read more →
Symmetric MatrixA square matrix satisfying A=ATA = A^TRead more →Inverse MatrixA square matrix A−1A^{-1} such that AA−1=A−1A=IAA^{-1} = A^{-1}A = IRead more →Singular MatrixA square matrix AA with det⁡(A)=0\det(A) = 0Read more →RankThe number of linearly independent columns (equivalently, rows) in a matrix:
rank(A)=dim⁡(Col(A))=dim⁡(Row(A))\text{rank}(A) = \dim(\text{Col}(A)) = \dim(\text{Row}(A))
Read more →
TraceThe sum of the main diagonal entries of a square matrix:
tr(A)=a11+a22+⋯+ann=∑i=1naii\text{tr}(A) = a_{11} + a_{22} + \cdots + a_{nn} = \sum_{i=1}^{n} a_{ii}
Read more →
Diagonal MatrixA square matrix where aij=0a_{ij} = 0 for all i≠ji \neq jRead more →Positive Definite MatrixA symmetric matrix AA satisfying xTAx>0\mathbf{x}^T A \mathbf{x} > 0 for all nonzero x\mathbf{x}Read more →TransposeThe matrix ATA^T obtained by swapping rows and columns: (AT)ij=aji(A^T)_{ij} = a_{ji}Read more →Main DiagonalThe entries a11,a22,a33,…a_{11}, a_{22}, a_{33}, \ldots whose row index equals their column indexRead more →Zero MatrixThe matrix 00 with every entry equal to zeroRead more →Scalar MatrixA diagonal matrix whose diagonal entries are all the same number: cIcIRead more →Skew-Symmetric MatrixA square matrix equal to the negative of its transpose: AT=−AA^T = -ARead more →Triangular MatrixA square matrix with zeros on one side of the main diagonalRead more →Permutation MatrixA square matrix with exactly one entry equal to 11 in each row and each column, and 00 everywhere else — the identity matrix with its rows…Read more →Nilpotent MatrixA square matrix some power of which is the zero matrix: Nk=0N^k = 0Read more →Idempotent MatrixA square matrix that equals its own square: P2=PP^2 = PRead more →Involutory MatrixA square matrix that is its own inverse: A2=IA^2 = IRead more →ConformabilityThe shape condition under which a matrix operation is definedRead more →Element-wise OperationAn operation applied independently at each position, so the entry at (i,j)(i, j) of the result depends only on the entries at (i,j)(i, j) of the inputsRead more →Matrix Square RootA matrix BB with B2=AB^2 = A, or more loosely BBT=ABB^T = ARead more →Spectral NormThe largest factor by which a matrix can stretch any vector:
∥A∥2=max⁡x≠0∥Ax∥∥x∥\|A\|_2 = \max_{\mathbf{x} \neq \mathbf{0}} \frac{\|A\mathbf{x}\|}{\|\mathbf{x}\|}
Read more →
Condition NumberThe ratio of the largest to the smallest singular value: κ(A)=σmax⁡/σmin⁡\kappa(A) = \sigma_{\max} / \sigma_{\min}Read more →
DeterminantA scalar det⁡(A)∈R\det(A) \in \mathbb{R} assigned to every square matrix, defined recursively via cofactor expansionRead more →MinorThe determinant of the submatrix obtained by deleting row ii and column jj from a matrix:
Mij=det⁡(A^ij)M_{ij} = \det(\hat{A}_{ij})
Read more →
CofactorA signed minor, with sign determined by the position (i,j)(i,j):
Cij=(−1)i+jMijC_{ij} = (-1)^{i+j} M_{ij}
Read more →
Cofactor Matrix (Adjugate)The transpose of the matrix of cofactors of AA:
adj(A)=CT\text{adj}(A) = C^T
Read more →
Cofactor ExpansionComputing a determinant by expanding along any row or column:
det⁡A=∑jaij Cij\det A = \sum_{j} a_{ij}\,C_{ij}
Read more →
Sarrus's RuleA shortcut for 3×33 \times 3 determinants: add the three products along the down-right diagonals, subtract the three along the down-left diagonalsRead more →AdjugateThe transpose of the cofactor matrix: adj(A)=CT\text{adj}(A) = C^TRead more →Cramer's RuleFor a square system Ax=bA\mathbf{x} = \mathbf{b} with det⁡A≠0\det A \neq 0: xi=det⁡(Ai)det⁡Ax_i = \dfrac{\det(A_i)}{\det A}, where AiA_i is AA with its ii-th column…Read more →OrientationThe handedness of an ordered set of vectors, read off the sign of the determinantRead more →
System of Linear EquationsA collection of equations Ax=bA\mathbf{x} = \mathbf{b} where AA is an m×nm \times n matrix and b∈Rm\mathbf{b} \in \mathbb{R}^mRead more →Augmented MatrixThe matrix formed by appending the right-hand side vector b\mathbf{b} as an additional column to the coefficient matrix AA, written…Read more →Row Echelon FormA matrix where:
• all zero rows are at the bottom
• each leading entry (pivot) is to the right of the pivot in the row above
• all entries below each…
Read more →
Reduced Row Echelon FormRow echelon form with the additional requirements:
• every pivot is 11
• each pivot is the only nonzero entry in its column
Read more →
PivotThe first nonzero entry in each row of a matrix in row echelon formRead more →Homogeneous SystemA system of linear equations in which every equation equals zero: Ax=0A\mathbf{x} = \mathbf{0}Read more →Coefficient MatrixThe matrix AA of coefficients of the unknowns when a system of linear equations is written as Ax=bA\mathbf{x} = \mathbf{b}Read more →Elementary Row OperationOne of three moves that leave a system's solution set unchanged: swap two rows, multiply a row by a non-zero constant, or add a multiple of one row…Read more →Gaussian EliminationThe algorithm that reduces a matrix to row echelon form using elementary row operationsRead more →Back-SubstitutionSolving an upper-triangular system from the bottom row upwardRead more →Forward SubstitutionSolving a lower-triangular system from the top row downwardRead more →Partial PivotingSwapping rows during elimination so that the largest available entry in the current column becomes the pivotRead more →Consistent SystemA system of linear equations that has at least one solutionRead more →Overdetermined SystemA system with more equations than unknownsRead more →LU DecompositionWriting a matrix as A=LUA = LU, with LL lower triangular and UU upper triangular; with row swaps, PA=LUPA = LURead more →Least-Squares SolutionFor an inconsistent system Ax=bA\mathbf{x} = \mathbf{b}, the x^\hat{\mathbf{x}} that minimizes ∥b−Ax^∥\|\mathbf{b} - A\hat{\mathbf{x}}\|; it satisfies the…Read more →ResidualThe error vector left by an approximate solution: r=b−Ax^\mathbf{r} = \mathbf{b} - A\hat{\mathbf{x}}Read more →Design MatrixThe matrix AA built from the data in a fitting problem: one row per observation, one column per unknown coefficientRead more →PseudoinverseThe matrix A+A^+ that plays the role of an inverse for a matrix that has none; for independent columns, A+=(ATA)−1ATA^+ = (A^TA)^{-1}A^TRead more →
Linear TransformationA function T:V→WT: V \to W between vector spaces that preserves addition and scalar multiplication:
$$T(\mathbf{u} + \mathbf{v}) = T(\mathbf{u}) +…
Read more →
Image (Range)The set of all output vectors of a linear transformation:
Im(T)={T(v)∣v∈V}\text{Im}(T) = \{T(\mathbf{v}) \mid \mathbf{v} \in V\}
Read more →
Matrix RepresentationA matrix AA such that T(v)=A[v]BT(\mathbf{v}) = A[\mathbf{v}]_{\mathcal{B}} for a chosen basis B\mathcal{B}Read more →Change of Basis MatrixA matrix PP that converts coordinates from one basis to another: [v]B′=P−1[v]B[\mathbf{v}]_{\mathcal{B}'} = P^{-1}[\mathbf{v}]_{\mathcal{B}}Read more →Similar MatricesMatrices AA and BB are similar if B=P−1APB = P^{-1}AP for some invertible matrix PPRead more →RotationA linear transformation that turns every vector through the same angle about the origin; in R2\mathbb{R}^2:
$$R_\theta = \begin{bmatrix} \cos\theta &…
Read more →
ReflectionA linear transformation that mirrors every vector across a line through the origin — or a plane, in three dimensionsRead more →Projection MatrixThe matrix PP sending every vector to its orthogonal projection onto a subspace; for a subspace with basis matrix AA:
P=A(ATA)−1ATP = A(A^TA)^{-1}A^T
Read more →
EigenvalueA scalar λ\lambda such that Av=λvA\mathbf{v} = \lambda\mathbf{v} for some nonzero vector v\mathbf{v}Read more →EigenvectorA nonzero vector v\mathbf{v} such that Av=λvA\mathbf{v} = \lambda\mathbf{v} for some scalar λ\lambdaRead more →EigenspaceThe set of all eigenvectors for a given eigenvalue λ\lambda, together with the zero vector — equivalently, the null space of $(A - \lambda…Read more →Characteristic PolynomialThe polynomial whose roots are the eigenvalues of AA, obtained by computing:
p(λ)=det⁡(A−λI)p(\lambda) = \det(A - \lambda I)
Read more →
Algebraic MultiplicityThe multiplicity of λ\lambda as a root of the characteristic polynomialRead more →Geometric MultiplicityThe dimension of the eigenspace associated with an eigenvalue λ\lambda:
$$\text{geo. mult.}(\lambda) = \dim(E_\lambda) = \dim(\text{Nul}(A - \lambda…
Read more →
Singular ValueA nonnegative scalar measuring how much a matrix stretches space along each principal direction, derived from the eigenvalues of ATAA^TA:
$$\sigma_i =…
Read more →
Diagonalizable MatrixA square matrix with a full set of nn linearly independent eigenvectors — equivalently, one that can be written as A=PDP−1A = PDP^{-1} with DD diagonalRead more →DiagonalizationFactoring a matrix as A=PDP−1A = PDP^{-1}, where the columns of PP are eigenvectors and DD carries the matching eigenvalues on its diagonalRead more →Defective MatrixA matrix with too few independent eigenvectors to be diagonalized: for some eigenvalue the geometric multiplicity is smaller than the algebraic…Read more →Dominant EigenvalueThe eigenvalue of largest absolute valueRead more →Rayleigh QuotientThe scalar
R(x)=xTA xxTxR(\mathbf{x}) = \frac{\mathbf{x}^T A\,\mathbf{x}}{\mathbf{x}^T \mathbf{x}}
Read more →
Quadratic FormA function q(x)=xTA xq(\mathbf{x}) = \mathbf{x}^T A\,\mathbf{x} built from a symmetric matrixRead more →Spectral DecompositionThe diagonalization of a symmetric matrix by an orthogonal matrix:
A=QΛQT=∑iλi qiqiTA = Q\Lambda Q^T = \sum_{i} \lambda_i\,\mathbf{q}_i \mathbf{q}_i^T
Read more →
Singular Value DecompositionThe factorization A=UΣVTA = U\Sigma V^T with UU and VV orthogonal and Σ\Sigma a rectangular diagonal matrix of singular values in decreasing orderRead more →
Inner ProductA function ⟨⋅,⋅⟩:V×V→R\langle \cdot, \cdot \rangle: V \times V \to \mathbb{R} satisfying symmetry, linearity, and positive-definitenessRead more →Orthogonal VectorsVectors u\mathbf{u} and v\mathbf{v} are orthogonal if ⟨u,v⟩=0\langle \mathbf{u}, \mathbf{v} \rangle = 0Read more →Orthogonal SetA set of vectors {v1,…,vk}\{\mathbf{v}_1, \ldots, \mathbf{v}_k\} where ⟨vi,vj⟩=0\langle \mathbf{v}_i, \mathbf{v}_j \rangle = 0 for all i≠ji \neq jRead more →Orthonormal SetAn orthogonal set where every vector is a unit vector: ⟨vi,vj⟩=δij\langle \mathbf{v}_i, \mathbf{v}_j \rangle = \delta_{ij}Read more →Orthogonal ComplementThe set of all vectors in VV that are orthogonal to every vector in a subspace WW:
$$W^\perp = \{\mathbf{v} \in V \mid \langle \mathbf{v},…
Read more →
Orthogonal MatrixA square matrix QQ satisfying QTQ=QQT=IQ^TQ = QQ^T = IRead more →Gram-Schmidt ProcessThe procedure that turns any linearly independent set into an orthonormal set spanning the same spaceRead more →QR DecompositionWriting a matrix with independent columns as A=QRA = QR, with QQ orthogonal and RR upper triangularRead more →Cholesky FactorizationWriting a positive definite matrix as A=LLTA = LL^T with LL lower triangular and positive diagonalRead more →
View All Linear Algebra Terms and Definitions →

Matrix decompositions

Explore Matrix decompositions →
Overview of matrix decompositions: LU, QR, Cholesky, spectral, and SVD. When to use each factorization, computational costs, relationships between decompositions, and applications.
Explore Matrix decompositions →

Row operations and the determinant

Explore Row operations and the determinant →
Learn matrix determinants: 2×2 and 3×3 formulas, cofactor expansion, Sarrus rule, row operations, singular vs invertible matrices, geometric interpretation as volume and orientation, and applications.
Explore Row operations and the determinant →

Eigenvalues and Eigenvectors

Explore Eigenvalues and Eigenvectors →
Learn eigenvalues and eigenvectors: definition, characteristic equation, eigenspaces, geometric meaning, worked examples, trace/determinant relationships, and applications.
Explore Eigenvalues and Eigenvectors →

Solving A x = b

Explore Solving A x = b →
Systems of linear equations: matrix form Ax = b, augmented matrix, three possible outcomes, geometric interpretation, row operations, echelon form, homogeneous systems, and solvability conditions.
Explore Solving A x = b →

Matrices in Linear Algebra

Explore Matrices in Linear Algebra →
Explore matrices in linear algebra through our detailed guide. Starting with matrix definitions and notations, the page explains matrix structure, elements, and indexing. You will learn to distinguish between different matrix types — from basic row and column matrices to more complex square matrices. The guide also covers essential matrix properties and dives into special cases of square matrices like diagonal and triangular forms. Each topic features clear mathematical notation and visual examples to reinforce your understanding of these fundamental concepts.
Inside the Matrix Guide
Definitions and Notations — how matrices are written using different types of brackets (square, parentheses, vertical bars) and basic matrix notation conventions
Elements, Structure and Indexing — how matrix elements are organized in rows and columns, the 1-based indexing system, and referencing specific elements by row and column indices
Types of Matrices — classifications based on shape (column, row, rectangular, square) and content type (numeric, variable/symbolic, mixed, zero)
Matrix Properties — size/dimension, rank, determinant, eigenvalues/eigenvectors, and trace, and their importance in matrix operations and transformations
Square Matrices and Special Cases — special diagonal patterns (diagonal, upper and lower triangular) and element relationships (symmetric, skew-symmetric, identity, scalar)
Explore Matrices in Linear Algebra →

Orthogonality in Linear Algebra

Explore Orthogonality in Linear Algebra →
Learn orthogonality in linear algebra: orthogonal vectors, complements, projections, inner products, orthonormal bases, Gram-Schmidt process, and least-squares approximation.
Explore Orthogonality in Linear Algebra →

Linear Transformations

Explore Linear Transformations →
Linear transformations: definition, examples in Rⁿ and abstract spaces, non-examples, basis determination, matrix connection, properties, composition, and geometric interpretation.
Explore Linear Transformations →

[Four subspaces](!/linear-algebra/vector-spaces/fundamental-spaces)

Explore [Four subspaces](!/linear-algebra/vector-spaces/fundamental-spaces) →
Vector spaces in linear algebra: ten axioms, Rⁿ and abstract examples, subspaces, linear independence, span, basis, dimension, and the four fundamental subspaces of a matrix.
Explore [Four subspaces](!/linear-algebra/vector-spaces/fundamental-spaces) →

What Is a Vector

Explore What Is a Vector →
Explore What Is a Vector →

Linear Algebra Calculators

3 toolsExplore Linear Algebra Calculators →
Step-by-step calculators for the core computations of linear algebra: solve systems of linear equations, carry out matrix operations, and work with vectors — every calculator shows its full working, one operation at a time.
Explore Linear Algebra Calculators →

Interactive Tools

Linear Algebra Symbols Reference

View Linear Algebra Symbols →

Our Linear Algebra Symbols page presents a well-organized collection of notation fundamental to matrix theory and vector spaces. This reference serves as a valuable resource for students and practitioners working with linear systems.

The page features symbols categorized by their mathematical applications, including matrix operations (A⊤, det(A), tr(A)), vector spaces (ℝⁿ, ⟨v,w⟩, ∥v∥), and eigenvalue concepts (Av = λv). It covers advanced topics like matrix decompositions (LU, QR, SVD) and linear transformations, alongside practical notation for representing matrices and vectors in LaTeX.

Every symbol includes its proper mathematical notation, corresponding LaTeX code for typesetting, and a brief explanation of its mathematical significance — making this an indispensable reference for anyone working with linear algebra in academic research or applications.

View Linear Algebra Symbols →