Re: Simplifying radicals
- To: mathgroup at smc.vnet.net
- Subject: [mg122307] Re: Simplifying radicals
- From: Dana DeLouis <dana01 at me.com>
- Date: Mon, 24 Oct 2011 05:14:58 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
> the principal cube root of a negative number will be complex ... > Is there any EASY way I can simply ask for the cube root of -729 and get -9? Hi. Not the best way, but just to mention an alternative: Power[-729., 1/3] 4.5 +7.79423 I Yep, it's complex like you mentioned. The -Easy- way is to add the negative sign in front of the answer. Power[-729., 1/3] //Abs 9. = = = = = = = = = HTH Dana DeLouis On Oct 20, 7:49 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