Difference between revisions of "Lambert W"

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The Lambert $W$ function is the (multi-valued) inverse of the function $g(x)=xe^{x}$. The function $g$ is not [[injective]] because [http://www.wolframalpha.com/input/?i=plot+y%3Dxe^x+for+-1%3Cy%3C2 its graph] does not pass the "horizontal line test". Therefore the inverse function is multi-valued and not unique. This yields two branches of the $W$ function.
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__NOTOC__
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The Lambert $W$ function is the (multi-valued) function that satisfies the equation
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$$z=W(z)e^{W(z)}.$$
  
 
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<gallery>
 
<gallery>
File:lambertwplot.png|Graph of branches $W_0(x)$ and $W_1(x)$ on $[-1,1]$.
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File:Lambertw0plot.png|Plot of the principal branch $W_0$.
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File:Complexlambertw0.png|[[Domain coloring]] of [[analytic continuation]] of branch $W_0(x)$ to $\mathbb{C}$.
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File:Complexlambertw-1.png|[[Domain coloring]] of [[analytic continuation]] of branch $W_{-1}(x)$ to $\mathbb{C}$.
 
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</gallery>
 
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=Properties=
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=Videos=
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*[https://www.youtube.com/watch?v=AJD8kh3DSAM 6: Recursion, Infinite Tetrations and the Lambert W Function (4 August 2014)]
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=External links=
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*[http://arxiv.org/pdf/1003.1628.pdf Having fun with the Lambert $W(x)$ function]
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=See also=
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[[Lambert W0]]<br />
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[[Lambert W1]]<br />
  
 
=References=
 
=References=
[http://arxiv.org/pdf/1003.1628.pdf Having fun with the Lambert $W(x)$ function]
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* {{PaperReference|On the Lambert W function|1996|R. M. Corless|author2=G. H. Gonnet|author3=D.E.G. Hare|author4=D.J. Jeffrey|author4=D.E. Knuth|prev=findme|next=findme}} $(1.5)$
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[[Category:SpecialFunction]]

Latest revision as of 18:24, 16 June 2018

The Lambert $W$ function is the (multi-valued) function that satisfies the equation $$z=W(z)e^{W(z)}.$$

Properties

Videos

External links

See also

Lambert W0
Lambert W1

References