FactorList

FactorList[poly]

gives a list of the factors of a polynomial, together with their exponents.

Details and Options

  • The first element of the list is always the overall numerical factor. It is {1,1} if there is no overall numerical factor.
  • FactorList[poly,Modulus->p] factors modulo a prime p.
  • FactorList[poly,GaussianIntegers->True] allows Gaussian integer coefficients.
  • FactorList[poly,Extension->{a1,a2,}] allows coefficients that are arbitrary rational combinations of the ai.

Examples

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Basic Examples  (2)

List the irreducible factors of polynomials:

List the irreducible factors of multivariate polynomials:

Scope  (8)

Basic Uses  (4)

A univariate polynomial:

A multivariate polynomial:

A polynomial with multiple factors:

A rational function:

Advanced Uses  (4)

The irreducible factors over the Gaussian integers:

The irreducible factors over an algebraic extension:

The irreducible factors over the integers modulo 2:

List factors of non-polynomial expressions:

Options  (5)

Extension  (2)

Factor over algebraic number fields:

Extension->Automatic automatically extends to a field that covers the coefficients:

GaussianIntegers  (1)

Factor over Gaussian integers:

Modulus  (1)

Factor over finite fields:

Trig  (1)

Factor a trigonometric expression:

Applications  (2)

FactorList can be useful in determining the behavior of functions:

has roots at and , at it does not cross the axis, and at it crosses the axis:

Show that a polynomial is a perfect square:

Compute the factors and note that the constant factor is positive:

Extract the exponents of nonconstant factors:

Check that every factor has even exponent and thus is a square:

Properties & Relations  (3)

FactorList gives a list of irreducible factors:

This multiplies the factors together:

Factor gives a product of factors:

Expand combines all the factors back together:

FactorSquareFreeList gives a list of square-free factors:

FactorInteger gives a list of prime factors of an integer:

Wolfram Research (1988), FactorList, Wolfram Language function, https://reference.wolfram.com/language/ref/FactorList.html (updated 1996).

Text

Wolfram Research (1988), FactorList, Wolfram Language function, https://reference.wolfram.com/language/ref/FactorList.html (updated 1996).

BibTeX

@misc{reference.wolfram_2021_factorlist, author="Wolfram Research", title="{FactorList}", year="1996", howpublished="\url{https://reference.wolfram.com/language/ref/FactorList.html}", note=[Accessed: 01-August-2021 ]}

BibLaTeX

@online{reference.wolfram_2021_factorlist, organization={Wolfram Research}, title={FactorList}, year={1996}, url={https://reference.wolfram.com/language/ref/FactorList.html}, note=[Accessed: 01-August-2021 ]}

CMS

Wolfram Language. 1988. "FactorList." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 1996. https://reference.wolfram.com/language/ref/FactorList.html.

APA

Wolfram Language. (1988). FactorList. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/FactorList.html