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Re: How to get sqrt(Year^2)===Year?

• To: mathgroup at smc.vnet.net
• Subject: [mg75784] Re: How to get sqrt(Year^2)===Year?
• From: siewsk at bp.com
• Date: Thu, 10 May 2007 05:20:57 -0400 (EDT)
• References: <f1s1v4$fip$1@smc.vnet.net>

On May 9, 6:49 pm, Hatto von Aquitanien <a... at AugiaDives.hre> wrote:
> If I have some expression which takes the square root of a square, it
> evaluates leaving the whole square root expression unchanged.
>
> Year == (Year^2)^(1/2)
>
> just returns what I entered when evaluated.
>
> Year == Year
>
> evaluates to True.
>
> How do I persuade Mathematica to evaluate the first expression completely?
> --http://www.dailymotion.com/video/x1ek5w_wtc7-the-smoking-gun-of-911-u...http://911research.wtc7.nethttp://vehme.blogspot.com
> Virtus Tutissima Cassis

In[1]:= Assuming[ {y>0} ,
  answer = Simplify[  Sqrt[ y^8 ]  ]
]

Out[1]:=  y^4