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Re: sqrt(x^2) = x

• To: mathgroup at smc.vnet.net
• Subject: [mg61189] Re: sqrt(x^2) = x
• From: "Francisco Javier" <pacoga at ctv.es>
• Date: Wed, 12 Oct 2005 01:42:23 -0400 (EDT)
• References: <difreg$fg6$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Francisco Javier a formulé ce martes :
> Dear all, I am new in this group
>
> How can I tell Mathematica that I want to simplify all expressions like 
> Sqrt[x^2] as x, whithout taking into account that x is or not a 
> positive real number?
>
> Thank you very much

Dear F.Jaccard and Ruth for your answers, but what I really mean has 
not a such simple solution.

I want to "teach" to Mathematica that in next calculations Sqrt[x^2] is 
equivalent to x,

I have tried

Unprotect[Sqrt];
Sqrt[(x_)^2] := x;

This seems works fine then with calculations like

Sqrt[y^2]
y

but it fails with

Sqrt[x^2 y^4]

or even with

Sqrt[x^2 y^4]

Any ideas?

-- 
----
Francisco Javier García Capitán
http://garciacapitan.auna.com