Algebraic number

Revision as of 21:25, 26 September 2008 by Herefishyfishy1 (talk | contribs)

A complex number is said to be algebraic if it is a root of a polynomial with rational coefficients. Examples include $\frac{1}{3}$, $\sqrt{2}+\sqrt{3}$, $i$, and $\frac{4+\sqrt[27]{19}}{\sqrt[3]{4}+\sqrt[7]{97}}$. A number that is not algebraic is called a transcendental number, such as $e$ or $\pi$.

Number of algebraic numbers

Although it seems that the number of algebraic numbers is large, there are only countably many of them. That is, the algebraic numbers have the same cardinality as the natural numbers.

Algebraic numbers are studied extensively in algebraic number theory.

Properties

  • All of the rational numbers are algebraic.
  • It is NOT necessary that an algebraic number is rational.

This article is a stub. Help us out by expanding it.

Invalid username
Login to AoPS