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Strange behaviour of Simplify

• To: mathgroup at smc.vnet.net
• Subject: [mg79008] Strange behaviour of Simplify
• From: Andreas Maier <andimai at web.de>
• Date: Sun, 15 Jul 2007 01:14:02 -0400 (EDT)

Hi,

i'm trying to simplify the following expression

In:= gamma=c Sqrt[g00])/Sqrt[c^2 g00 + g11 v^2]
In:=LeafCount[gamma]
Out:=52

using Simplify

In:= gamma2=Simplify[gamma, {Sqrt[g00] > 0, c > 0 }]

Out:=c/Sqrt[c^2 + (g11 v^2)/g00]
In:=LeafCount[gamma2]
Out:=44

Why is Mathematica (I'm using V6.0) able to cancel Sqrt[g00], but is
not
able to cancel c? I also tried ComplexityFunction->LeafCount, which
should work, because

In:=gamma3=1/Sqrt[1 + (g11 v^2)/(c^2 g00)]
In:=LeafCount[gamma3]
Out:=43

the LeafCount of gamma3 is smaller than gamma2, but it doesn' work.
Can anybody tell me, how i can transform gamma to gamma3 in
Mathematica?

Andreas Maier

• Follow-Ups:
  • Re: Strange behaviour of Simplify
    • From: Andrzej Kozlowski <akoz@mimuw.edu.pl>