Re: Simplifying radicals
- To: mathgroup at smc.vnet.net
- Subject: [mg122292] Re: Simplifying radicals
- From: Ray Koopman <koopman at sfu.ca>
- Date: Sun, 23 Oct 2011 06:26:33 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <j7p1s8$5ko$1@smc.vnet.net>
On Oct 20, 4:49 am, Tom De Vries <tidetable... at gmail.com> wrote:
> Hi, I'm working with some introductory topics in radicals.
>
> I know that Mathematica assumes things about the domain used in
> problems, so the principal cube root of a negative number will be
> complex... or something like that..
>
> I'm way down at the lower high school level simply working with cube
> roots of negative numbers and wanting a negative number result.
>
> I know there are ways of using assumptions and solving over the reals, etc.
>
> Is there any EASY way I can simply ask for the cube root of -729 and get -9?
>
> TOM
qbrt = Piecewise[{{-(-#)^(1/3),#<0}},#^(1/3)]&