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Re: Re: Help with Root function

• To: mathgroup at smc.vnet.net
• Subject: [mg79498] Re: [mg79439] Re: Help with Root function
• From: Murray Eisenberg <murray at math.umass.edu>
• Date: Sat, 28 Jul 2007 05:25:49 -0400 (EDT)
• Organization: Mathematics & Statistics, Univ. of Mass./Amherst
• References: <f89q55$5nu$1@smc.vnet.net> <200707270941.FAA02001@smc.vnet.net>
• Reply-to: murray at math.umass.edu

Not as easy to discover as one might hope, but possible. In Mathematica 6...

First, I would look up Root in the Documentation Center, going to its 
"home page" -- most likely by having evaluated ?Root in my notebook and 
clicking the documentation link at the end of the brief information 
provided in the notebook.

Second, I would search through the Root home page to try to find an 
example where the roots are expressed in terms of radicals. I find none!

Third, I would have gone to one of the links on the page. Under "See 
Also" near the bottom of the page, I MIGHT have spotted ToRadicals, and 
if I did I would certainly look there without ever having seen that before.

But more likely I would have tried the Tutorials links at the bottom of 
the page.   So...

Fourth, I would try to Solving Equations tutorial, only to find nothing 
relevant there, so I'd go back to the Roots page.

Fifth, I try the Algebraic Numbers (since I know, mathematically, that a 
radical is an algebraic number).  And, aha!, there I find an example 
about using ToRadicals to convert a Root object to radicals.



jeremito wrote:
> Thank you all who offered the solution to this problem.  The answer
> is:
> 
> Eigenvalues[B]//ToRadicals
> 
> How simple, if you know how to do it.  My follow-up question is:
> 
> How could I (or anyone) have found that on their own?  I searched in
> the documentation, but couldn't find it until I knew what to search
> for.

-- 
Murray Eisenberg                     murray at math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower      phone 413 549-1020 (H)
University of Massachusetts                413 545-2859 (W)
710 North Pleasant Street            fax   413 545-1801
Amherst, MA 01003-9305

• References:
  • Re: Help with Root function
    • From: jeremito <jeremit0@gmail.com>