Lambert W function


Lambert’s W functionMathworldPlanetmath is the inverse of the function f: given by f(x):=xex. That is, W(x) is the complex valued function that satisfies

W(x)eW(x)=x,

for all x. In practice the definition of W(x) requires a branch cut, which is usually taken along the negative real axis. Lambert’s W function is sometimes also called product log function.

This function allow us to solve the functional equation

g(x)g(x)=x

since

g(x)=eW(ln(x)).

1 References

A site with good information on Lambert’s W function is Corless’ page http://kong.apmaths.uwo.ca/ rcorless/frames/PAPERS/LambertW/“On the Lambert W Function

Title Lambert W function
Canonical name LambertWFunction
Date of creation 2013-03-22 12:40:48
Last modified on 2013-03-22 12:40:48
Owner drini (3)
Last modified by drini (3)
Numerical id 8
Author drini (3)
Entry type Definition
Classification msc 33B30
Synonym product log