Services & Resources / Wolfram Forums
MathGroup Archive
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2001

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

Search the Archive

Re: Solutions that are not solutions

  • To: mathgroup at
  • Subject: [mg32077] Re: [mg32049] Solutions that are not solutions
  • From: BobHanlon at
  • Date: Sat, 22 Dec 2001 04:22:51 -0500 (EST)
  • Sender: owner-wri-mathgroup at

In a message dated 12/21/01 4:32:36 AM, psino at writes:

>I'm trying to solve a system as follows:
>Solve[{X.A==Transpose[A].X, Det[X]==1},
>Mathematica 4.1 gives two solutions:
>However, X1 is not a solution:
>Could anybody explain this behaviour?

I only get one solution.


"4.1 for Power Macintosh (November 2, 2000)"


eqns = {X.A==Transpose[A].X,Det[X]==1};

soln = Flatten[Solve[eqns,{x,y,z,t,u,v,w}]]

{x -> (a*t*y^2 + a*v*y^2 - w*y^2 - 1)/
    (a^2*y^2), z -> a*y, u -> a*y}

X /. soln

{{0, y, a*y}, {y, (a*t*y^2 + a*v*y^2 - 
     w*y^2 - 1)/(a^2*y^2), t}, 
  {a*y, v, w}}

eqns /. soln

{True, True}

Bob Hanlon
Chantilly, VA  USA

  • Prev by Date: Re: Replacement Rule
  • Next by Date: Re: Solutions that are not solutions
  • Previous by thread: Re: solutions that are not solutions
  • Next by thread: Re: Solutions that are not solutions