# Finding the Structure of a Polynomial

PolynomialQ[expr,x] | test whether expr is a polynomial in x |

PolynomialQ[expr,{x_{1},x_{2},...}] | test whether expr is a polynomial in the |

Variables[poly] | a list of the variables in poly |

Exponent[poly,x] | the maximum exponent with which x appears in poly |

Coefficient[poly,expr] | the coefficient of expr in poly |

Coefficient[poly,expr,n] | the coefficient of in poly |

Coefficient[poly,expr,0] | the term in poly independent of expr |

CoefficientList[poly,{x_{1},x_{2},...}] | generate an array of the coefficients of the in poly |

CoefficientRules[poly,{x_{1},x_{2},...}] | get exponent vectors and coefficients of monomials |

Finding the structure of polynomials written in expanded form.

Here is a polynomial in two variables.

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This is the polynomial in expanded form.

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This expression, however, is not a polynomial in

.

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Variables gives a list of the variables in the polynomial

.

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This gives the maximum exponent with which

appears in the polynomial

. For a polynomial in one variable,

Exponent gives the degree of the polynomial.

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Coefficient[poly, expr] gives the total coefficient with which

expr appears in

poly. In this case, the result is a sum of two terms.

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This picks out the coefficient of

in

.

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CoefficientList gives a list of the coefficients of each power of

, starting with

.

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For multivariate polynomials,

CoefficientList gives an array of the coefficients for each power of each variable.

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It is important to notice that the functions in this tutorial will often work even on polynomials that are not explicitly given in expanded form.

Many of the functions also work on expressions that are not strictly polynomials.

Without giving specific integer values to

,

, and

, this expression cannot strictly be considered a polynomial.

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Exponent[expr, x] still gives the maximum exponent of

in

expr, but here has to write the result in symbolic form.

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