Difference between revisions of "Thomae function"

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File:Thomae.png|Plot of the Thomae function.
 
File:Thomae.png|Plot of the Thomae function.
 
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=Properties=
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<strong>Theorem:</strong> The Thomae function is [[continuous]] at all [[irrational number|irrational numbers]] and discontinuous at all [[rational number|rational numbers]].
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<strong>Proof:</strong> █
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<strong>Theorem:</strong> The Thomae function has a (strict) [[local maximum]] at each [[rational number]].
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<strong>Proof:</strong> █
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Revision as of 20:35, 11 April 2015

Thomae's function is given by the formula $$f(x) =\begin{cases} 1 & \text{if } x= 0 \\ \tfrac1{q} & \text{if } x = \tfrac{p}{q}\\ 0 & \text{if } x \in \mathbb{R}-\mathbb{Q}. \end{cases}$$


Properties

Theorem: The Thomae function is continuous at all irrational numbers and discontinuous at all rational numbers.

Proof:

Theorem: The Thomae function has a (strict) local maximum at each rational number.

Proof: