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| − | '''Algebraic numbers''', are real numbers which are roots of some finite degree polynomial with integer coefficients. Examples of Algebraic Numbers are 2, 1/3, and <math>\sqrt{2}</math>. | + | '''Algebraic numbers''', are real numbers which are roots of some finite degree [[polynomial]] with integer coefficients. Examples of algebraic numbers are 2, 1/3, and <math>\sqrt{2}</math>. |
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| − | In contrast, [[transcendental numbers]] are real numbers which are not roots of any finite degree polynomial with integer coefficients. The most well-known transcendental numbers are [[e]] and <math>\pi</math> ([[pi]]). | + | In contrast, [[transcendental numbers]] are real numbers which are not roots of any finite degree polynomial with integer coefficients. The most well-known transcendental numbers are [[e]] and <math>\pi</math> ([[pi]]), though this must be proven using advanced [[calculus]] or [[number theory]]. |
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| − | The set of Algebraic Numbers is countably [[infinite]]. This follows from the fact that the set of finite degree polynomials with integer coefficients is countably [[infinite]]. | + | The set of algebraic numbers is countably [[infinite]]. This follows from the fact that the set of finite degree polynomials with integer coefficients is countably [[infinite]]. Conversely, the set of transcendental numbers is [[uncountable]] because for any finite degree polynomial with integer coefficients there are uncountably many numbers which are not solutions to it. |
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| | + | The algebraic numbers are closed under [[addition]], [[subtraction]], [[multiplication]], [[division]], [[square root]]s, [[radical]]s, and [[exponentiation]]. These properties imply that the algebraic numbers are an [[algebraically closed]] [[field]]. |
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| | + | If a is an algebraic number and t is a transcendental number, then a+t, a-t, at, a/t, a<sup>t</sup>, and t<sup>a</sup> are all transcendental. |
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| | + | A [[random]] real number is probably transcendental, though the exact value of this [[probability]] has baffled [[statistician]]s for almost 100 years. |
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| | [[Category:Mathematics]] | | [[Category:Mathematics]] |