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{{Not to be confused with|Quartic (disambiguation){{!}}Quartic}}
{{wiktionary|quadratic}}
In mathematics, the term '''quadratic''' describes something that pertains to [[Square (algebra)|squares]], to the operation of squaring, to terms of the second [[degree of a polynomial|degree]], or equations or formulas that involve such terms.  ''Quadratus'' is [[Latin]] for ''square''.

== Mathematics ==
=== Algebra (elementary and abstract) ===
* [[Quadratic function]] (or quadratic polynomial), a polynomial function that contains terms of at most second degree
** [[Complex quadratic polynomial]]s, are particularly interesting for their sometimes chaotic properties under iteration
* [[Quadratic equation]], a polynomial equation of degree 2 (reducible to 0 = ''ax''<sup>2</sup> + ''bx'' + ''c'')
* [[Quadratic formula]], calculation to solve a quadratic equation for the independent variable (''x'')
* [[Quadratic field]], an algebraic number field of degree two over the field of rational numbers
* [[Quadratic irrational]] or "quadratic surd", an irrational number that is a root of a quadratic polynomial

=== Calculus ===
* [[Quadratic integral]], the integral of the reciprocal of a second-degree polynomial

=== Statistics and stochastics ===
* [[Quadratic form (statistics)]], scalar quantity ε'Λε for an ''n''-dimensional square matrix
* [[Quadratic mean]], the square root of the mean of the squares of the data
* [[Quadratic variation]], in stochastics, useful for the analysis of Brownian motion and martingales

=== Number theory ===
* [[Quadratic reciprocity]], a theorem from number theory
* [[Quadratic residue]], an integer that is a square modulo ''n''
* [[Quadratic sieve]], a modern integer factorization algorithm

=== Other mathematics ===
* [[Quadratic convergence]], in which the distance to a convergent sequence's limit is squared at each step
* [[Quadratic differential]], a form on a Riemann surface that locally looks like the square of an abelian differential
* [[Quadratic form]], a homogeneous polynomial of degree two in any number of variables
* [[Quadratic programming]], a special type of mathematical optimization problem
* [[Quadratic growth]], an asymptotic growth rate proportional to a quadratic function
* [[Periodic points of complex quadratic mappings]], a type of graph that can be used to explore stability in control systems
* [[Bézier curve|Quadratic Bézier curve]], a type of Bézier curve

== Computer science ==
* [[Quadratic probing]], a scheme in computer programming for resolving collisions in hash tables
* [[Quadratic classifier]], used in machine learning to separate measurements of two or more classes of objects
* [[Quadratic time]], in referring to algorithms with quadratic time complexity

== Other ==
*[[Quadratic (collection)|''Quadratic'' (collection)]], a 1953 collection of science fiction novels by Olaf Stapledon and Murray Leinster

==See also==
* {{look from}}
* {{in title}}
* [[Cubic (disambiguation)]], relating to a [[cube]] or [[degree of a polynomial|degree]] 3, as next higher above ''quadratic''
* [[Linear]], relating to a line or degree 1, as next lower below ''quadratic''
* [[Quad (disambiguation)]]
* [[Quadratic transformation (disambiguation)]]

{{mathematical disambiguation}}