On Wed, Jun 24, 2009 at 12:51 PM, Aaron S. Meurer<[email protected]> wrote: > > Or you could use the LambertW function. Maple gives > > solve(exp(x*(x-3))=2*(x-1)*(x-2),x); > 3/2+(1/2)*sqrt(1-4*LambertW(-(1/2)*exp(-2))), 3/2- > (1/2)*sqrt(1-4*LambertW(-(1/2)*exp(-2))), > 3/2+(1/2)*sqrt(1-4*LambertW(-1, -(1/2)*exp(-2))), 3/2- > (1/2)*sqrt(1-4*LambertW(-1, -(1/2)*exp(-2))) > > from ?LambertW: > > •The LambertW function satisfies > LambertW(x) * exp(LambertW(x)) = x . > •As the equation y exp(y) = x has an infinite number of solutions y > for each (non-zero) value of x, LambertW has an infinite number of > branches. Exactly one of these branches is analytic at 0. In Maple > this branch is referred to as the principal branch of LambertW, and is > denoted by LambertW(x). The other branches all have a branch point at > 0, and these branches are denoted in Maple by LambertW(k, x), where k > is any non-zero integer. (The principal branch can also be referred to > as LambertW(0, x)). > See also http://en.wikipedia.org/wiki/Lambertw > > I am surprized that mathematica does not use it. > > It doesn't look like SymPy has the LambertW function, unless I am > missing it.
Just do: In [1]: LambertW? Ondrej --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sympy?hl=en -~----------~----~----~----~------~----~------~--~---
