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Re: What to do in v. 6 in place of Miscellaneous`RealOnly

• To: mathgroup at smc.vnet.net
• Subject: [mg76678] Re: What to do in v. 6 in place of Miscellaneous`RealOnly
• From: dimitris <dimmechan at yahoo.com>
• Date: Fri, 25 May 2007 06:48:35 -0400 (EDT)
• References: <f33ork$l7l$1@smc.vnet.net>

Hi Helen.

I don't have version 6 but in case you don't know
there is a much more flexible package named
SwitchableRealOnly by Ted Ersek available at

http://library.wolfram.com/infocenter/MathSource/560/

Also if you want to avoid the use of any package you can
let your students defining their own "always real cubic root".

In[16]:=
RealCubicRoot[x_] := Sign[x]*Abs[x]^(1/3)

In[17]:=
Plot[RealCubicRoot[x], {x, -2, 2}]

Dimitris


 /  Helen Read       :
> Suppose my calculus students want to plot x^(1/3), for say {x,-8,8}. The
> problem, of course, is that Mathematica returns complex roots for x<0.
> In past versions of Mathematica, we could get the desired real roots
> (and plot the function) by loading the package Miscellaneous`RealOnly. I
> guess we can still do it that way (and ignore the "obsolete package"
> message), but is there a suggested way of doing what we need in 6.0?
>
> --
> Helen Read
> University of Vermont