quadratic form

A "quadratic form" is a fundamental concept in mathematics, especially in algebra and statistics, involving expressions where variables are raised to the second power.

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Definition

C1Algebra

(technical, academic)A polynomial where each term is of degree two in a given number of variables.

Example

  • The expression x² + 5xy + y² is a quadratic form in the variables x and y.

C1Linear Algebra

(technical, academic)A function that maps a vector to a scalar, typically represented as xáµ€Ax, where x is a vector and A is a symmetric matrix.

Example

  • The quadratic form xáµ€Ax can be used to describe the curvature of surfaces.

C1Statistics

(technical, academic)A scalar quantity expressed as εᵀΛε, where ε is a vector of random variables and Λ is a symmetric matrix.

Example

  • In multivariate statistics, quadratic forms are used to test hypotheses about mean vectors.

Similar

Terms that have similar or relatively close meanings to "quadratic form":

multilinear formechelon formclosed formin formabsolute formnormal form