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MathGroup Archive 2006

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Simplify UnitStep expressions

  • To: mathgroup at
  • Subject: [mg69195] Simplify UnitStep expressions
  • From: "L. Dwynn Lafleur" <lafleur at>
  • Date: Fri, 1 Sep 2006 06:41:43 -0400 (EDT)
  • Organization: University of Louisiana at Lafayette
  • Sender: owner-wri-mathgroup at

The following is transcribed from a Mathematica 5.2 notebook in Windows XP:

In[1]:= Simplify[UnitStep[a-x/b], a-x/b > 0]
Out[1]= 1

In[2]:= Simplify[UnitStep[a-Pi/b], a-Pi/b > 0]
Out[2]= UnitStep[a-Pi/b]

Why does the second output different from the first?  I know it has 
something to do with the fact that Pi is internally defined in Mathematica 
because a similar result occurs Pi is replaced with E, but what logic is 
being followed?

 L. Dwynn Lafleur
 Professor of Physics
 University of Louisiana at Lafayette
 lafleur at

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