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MathGroup Archive 1997

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Factor[] and real numbers???

  • To: mathgroup at
  • Subject: [mg8785] Factor[] and real numbers???
  • From: sbecuwe at (Stefan.Becuwe)
  • Date: Thu, 25 Sep 1997 12:26:19 -0400
  • Sender: owner-wri-mathgroup at


According to the Mathematica Book, 
"Factor works only with exact Integer or Rational coefficients, not
 with Real numbers."
Knowing this, can anyone explain the following (strange?) results?
(I'm using Mathematica 2.2)
In[2]:= Factor[Pi x - Pi x^2]

Out[2]= Pi (1 - x) x

In[3]:= Factor[N[3/7,20] x - N[6/7,20]x^2]

Out[3]= 0.85714285714285714286 (0.5 - x) x

In[4]:= Factor[N[3/7,20] x - N[6/7,30]x^2]

Out[4]= 0.857142857142857142857142857143 (0.5 - x) x


Stefan Becuwe

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