eigenvalue of a matrix

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eigenvalue of a matrix

A student calculates the eigenvalue of a matrix on a chalkboard.

Definition

Noun: 1. (Mathematics): A scalar (a number) associated with a given square matrix. Specifically, it is a number λ (lambda) for which there exists a non-zero vector v such that when the matrix multiplies that vector, the result is simply the scalar λ times the original vector v. This relationship is the defining equation: A v = λ v. Equivalently, λ is an eigenvalue if the matrix (A - λI), where I is the identity matrix, has a determinant of zero.

Usage

The term is used in linear algebra to describe the special scalars that reveal fundamental properties of a linear transformation represented by the matrix, such as its stretching factors and directions of invariance. * Finding the eigenvalue of a matrix is a central problem in linear algebra. * The stability of a system is often determined by the eigenvalues of its coefficient matrix.

Examples
  • In the equation A x = λ x, the scalar λ is the eigenvalue of the matrix A.
  • To find the eigenvalues of a matrix, one must solve the characteristic equation det(A - λI) = 0.
  • A symmetric matrix is guaranteed to have real eigenvalues.
Advanced Usage
  • Multiplicity: An eigenvalue can have an (how many times it is a root of the characteristic polynomial) and a (the dimension of its associated eigenspace).
  • Spectrum: The set of all eigenvalues of a matrix is called its .
  • Dominant Eigenvalue: In many applied contexts, the eigenvalue with the largest absolute value (the or eigenvalue) is of particular importance, for example, in power iteration methods or analyzing population growth models.
Variants and Related Words
  • Eigenvalue (n): The more common, shortened form of the term. (e.g., "Calculate the eigenvalues.")
  • Characteristic Value (n): A direct synonym for eigenvalue.
  • Proper Value (n): Another, less common synonym.
  • Latent Root (n): A synonym occasionally used in certain fields like statistics.
  • Eigenvector (n): The non-zero vector v associated with a specific eigenvalue λ in the equation A v = λ v.
  • Eigenspace (n): The set of all eigenvectors associated with a particular eigenvalue λ, along with the zero vector.
Synonyms
  • Characteristic value
  • Proper value
  • Latent root
Related Phrases
  • Eigenvalue decomposition: A matrix factorization that expresses a matrix in terms of its eigenvalues and eigenvectors.
  • Eigenvalue problem: The mathematical problem of finding the eigenvalues (and often eigenvectors) of a matrix.
eigenvalue of a matrix

A student calculates the eigenvalue of a matrix on a chalkboard.

Noun
  1. (mathematics) any number such that a given square matrix minus that number times the identity matrix has a zero determinant