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MathGroup Archive 1998

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Strange behaviour of Solve[] for equation with numerical coeeficients

  • To: mathgroup at smc.vnet.net
  • Subject: [mg14655] Strange behaviour of Solve[] for equation with numerical coeeficients
  • From: Vladimir Bulatov <bulatov at dots.physics.orst.edu>
  • Date: Sat, 7 Nov 1998 02:10:03 -0500
  • Organization: Oregon State University
  • Sender: owner-wri-mathgroup at wolfram.com

Hi everybody, 

I have found strange result which Solve[] gives, when equations contains
numerical 
values. 
For example:
Solve[
 {1.*ib*z^2 + ia*(x^2 - y^2 + y*z - z^2 + ib*(-3*y + z)) == 0, 
   x^2*z + y^2*z - y*z^2 + ia*(-3x^2 - y^2 + x*z + y*z) + x*(-3*y*z -
z^2) == 0
 },             
 {ia,ib}
]

silently gives wrong result: 

{{ib->1,ia->z}}, 

However, if we remove 1. from first term in first equation we will have
correct result (long to be included here). 

Precise view of equation is not important, it happent almost always.

Any help would be appreciated. I really need to solve symbolically  a
little bit more complex equation. 

If it does matter, I use Mathematica 3.0 under Win95. 

All the best, 
      Vladimir

-- 
Dr. V.Bulatov,  Physics Department, Oregon State University,  301
Weniger Hall, Corvallis, OR,97331-6705, USA 
bulatov at dots.physics.orst.edu; http://www.physics.orst.edu/~bulatov/;
tel: 541-7371715


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