Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2006
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2006

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Why is the negative root?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg69491] Re: Why is the negative root?
  • From: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>
  • Date: Thu, 14 Sep 2006 06:55:22 -0400 (EDT)
  • Organization: Uni Leipzig
  • References: <ee8h8v$j48$1@smc.vnet.net>

Hi,

(Reduce[{z^3 - z^2 - b z - 1 == 0, b > 0, z > 0}, 
z] // ToRadicals) /.
b -> 3 // FullSimplify

gives

Sqrt[2]+z==1

And you should be more careful when you use // to 
apply

functions and look in what order the functions are 
used.

Regards

  Jens

<p-valko at tamu.edu> schrieb im Newsbeitrag 
news:ee8h8v$j48$1 at smc.vnet.net...
| (Reduce[{z^3-z^2- b z-1==0, b>0, z>0}, z] 
//ToRadicals)/.b->3.//Chop
|
| gives a negativ z:
|
| z == - 0.414214
|
| What am I doing wrong?
|
| Regards
| Peter
| 



  • Prev by Date: HELP!ListDensityPlot rectangular matrix
  • Next by Date: Re: Differential equation
  • Previous by thread: Re: Why is the negative root?
  • Next by thread: Re: Why is the negative root?