Difference between revisions of "Weierstrass nowhere differentiable function"

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=References=
 
=References=
 
[http://kryakin.org/at/hardy_1916_W.pdf]
 
[http://kryakin.org/at/hardy_1916_W.pdf]
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[[Category:SpecialFunction]]

Revision as of 18:33, 24 May 2016

The Weierstrass function is $$f(x)=\displaystyle\sum_{k=0}^{\infty} a^k \cos(b^k\pi x),$$ where $0<a<1$ and $b \in \{1,3,5,7,9,\ldots\}$ such that $ab > 1+\dfrac{3}{2}\pi$.

Properties

Theorem: The Weierstrass function $f$ is continuous everywhere but differentiable nowhere.

Proof:

References

[1]