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Re: branch of (-1)^(1/3)

• To: mathgroup at smc.vnet.net
• Subject: [mg94459] Re: branch of (-1)^(1/3)
• From: "sjoerd.c.devries at gmail.com" <sjoerd.c.devries at gmail.com>
• Date: Sun, 14 Dec 2008 07:36:08 -0500 (EST)
• References: <ghtjcj$r7f$1@smc.vnet.net>

There is a tutorial on this issue in the documentation centre (V7) at
tutorial/FunctionsThatDoNotHaveUniqueValues. It seems the branch cuts
and primal roots are fixed and not user selectable.

Cheers -- Sjoerd

 On Dec 12, 1:53 pm, "slawek" <hu... at site.pl> wrote:
> Is a simple way to choose the branch of (-1)^(1/3) ?
>
> Mathematica gives a (correct) non-real answer. It is ok, but I need the (=
-1)
> as the output when I input (1)^(1/3)  because I know that it is a solut=
ion
> of real-valued problem.
>
> Is any "standard way" to pick up a correct (i.e. arbitrary) root of
> (-1)^(1/n) instead the default?
>
> slawek

• Follow-Ups:
  • Re: Re: branch of (-1)^(1/3)
    • From: Murray Eisenberg <murray@math.umass.edu>