Re: New user question
- To: mathgroup at smc.vnet.net
- Subject: [mg20400] Re: New user question
- From: "Allan Hayes" <hay at haystack.demon.co.uk>
- Date: Tue, 26 Oct 1999 00:32:53 -0400
- References: <7uefh0$277@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Thomas Moriarty <moriarty at umd5.umd.edu> wrote in message news:7uefh0$277 at smc.vnet.net... > I have just begun to use/learn Mathematica. One of the first things I > tried was to Plot[x^(1/3),{x,-5,5}] and got error messages indicating that > the negatives^(1/3) were not machine level real numbers (or close to > that) - the positive side displayed ok. > > What am I doing wrong? > > Thanks > > Thomas, You are not doing anything wrong - its that in the complex numbers, which is what Mathematica uses, we have (-1)^(1/3) // ComplexExpand 1/2 + (I*Sqrt[3])/2 You might like to look at the standard add on package Miscellaneous`RealOnly` -- Allan --------------------- Allan Hayes Mathematica Training and Consulting Leicester UK www.haystack.demon.co.uk hay at haystack.demon.co.uk Voice: +44 (0)116 271 4198 Fax: +44 (0)870 164 0565