Difference between revisions of "Irrational numbers"
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Irrational numbers can never be expressed exactly using decimal notation with a finite number of digits. Instead it is common to write them using only enough significant digits to solve the problem at hand, followed by an ellipsis: | Irrational numbers can never be expressed exactly using decimal notation with a finite number of digits. Instead it is common to write them using only enough significant digits to solve the problem at hand, followed by an ellipsis: | ||
| − | :pi equals 3. | + | :pi equals 3.1415926... |
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| + | For many purposes, a good approximation of pi is: | ||
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| + | 355 / 113 = 3.1415929... | ||
==See also== | ==See also== | ||
[[Transcendental numbers]] | [[Transcendental numbers]] | ||
Revision as of 22:33, April 8, 2007
An irrational number is a number that cannot be expressed as the ratio of two integers. Irrational numbers together with rational numbers make up the set of real numbers.
Irrational numbers often arise as solutions to problems involoving rational numbers. For example, the square root of 2 is irrational. Other irrationals, such as pi, serve as fundamental constants in many mathematical problems.
Irrational numbers can never be expressed exactly using decimal notation with a finite number of digits. Instead it is common to write them using only enough significant digits to solve the problem at hand, followed by an ellipsis:
- pi equals 3.1415926...
For many purposes, a good approximation of pi is:
355 / 113 = 3.1415929...