Rational Function

A quotient of two polynomials P(z) and Q(z),


is called a rational function, or sometimes a rational polynomial function. More generally, if P and Q are polynomials in multiple variables, their quotient is called a (multivariate) rational function. The term "rational polynomial" is sometimes used as a synonym for rational function. However, this usage is strongly discouraged since by analogy with complex polynomial and integer polynomial, rational polynomial should properly refer to a polynomial with rational coefficients.

A rational function has no singularities other than poles in the extended complex plane. Conversely, if a single-values function has no singularities other than poles in the extended complex plane, then it is a rational function (Knopp 1996, p. 137). In addition, a rational function can be decomposed into partial fractions (Knopp 1996, p. 139).

See also

Abel's Curve Theorem, Closed Form, Fundamental Theorem of Symmetric Functions, Inside-Outside Theorem, Polynomial, Quotient-Difference Algorithm, Rational Integer, Rational Number, Rational Polynomial, Riemann Curve Theorem Explore this topic in the MathWorld classroom

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Flajolet, P. and Sedgewick, R. "Analytic Combinatorics: Functional Equations, Rational and Algebraic Functions.", K. "Rational Functions." §35 in Theory of Functions Parts I and II, Two Volumes Bound as One, Part I. New York: Dover, pp. 96 and 137-139, 1996.

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Rational Function

Cite this as:

Weisstein, Eric W. "Rational Function." From MathWorld--A Wolfram Web Resource.

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