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Re: Simplify Question

  • To: mathgroup at smc.vnet.net
  • Subject: [mg41671] Re: Simplify Question
  • From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
  • Date: Fri, 30 May 2003 03:56:18 -0400 (EDT)
  • Organization: Universitaet Leipzig
  • References: <bb4uq3$43d$1@smc.vnet.net>
  • Reply-to: kuska at informatik.uni-leipzig.de
  • Sender: owner-wri-mathgroup at wolfram.com

Hi,

do you like the output of

Sqrt[2]/Sqrt[1 + 1/x] // 
  FullSimplify[#, x > 0, 
      ComplexityFunction -> (If[Head[#] === Rational, 1, 0] &)] &

more ??

Regards
  Jens

Dana DeLouis wrote:
> 
> Hello.  Could someone offer an explanation or a solution on the following?  I am trying to simplify an equation that has a Sqrt in both the numerator and denominator.  I would like to have just one Sqrt function.
> 
> Sqrt[2]/Sqrt[1 + 1/x]
> Returns...
> Sqrt[2]/Sqrt[1 + 1/x]
> 
> I am aware that one has to be careful when simplifying Sqrt functions.
> However, I know that x will always be greater than zero, so I thought this would work.
> 
> FullSimplify[Sqrt[2]/Sqrt[1 + 1/x], x > 0]
> Returns the same equation...
> Sqrt[2]/Sqrt[1 + 1/x]
> 
> I even mention that x is Real...
> FullSimplify[Sqrt[2]/Sqrt[1 + 1/x], x > 0 && Element[x,Reals]]
> Sqrt[2]/Sqrt[1 + 1/x]
> 
> I still get a Sqrt over a Sqrt
> 
> However, if I change the number 2 in the numerator to a variable say t, to represent two, then it works...
> 
> FullSimplify[Sqrt[t]/Sqrt[1 + 1/x], x > 0]
> Sqrt[(t*x)/(1 + x)]
> 
> The above has only 1 Sqrt function.  :>)
> I can't seem to simplify the above by keeping 2 as 2, and not as a variable (t).
> 
> Help on FullSimplify has an example of a Sqrt in both the numerator and denominator.  The help example did not make any assumptions on x.
> 
> FullSimplify[Sqrt[(2 - x)/(3 + x)]/Sqrt[2 - x]]
> 
> Sqrt[1/(3 + x)]
> 
> Thank you in advance.  This simple example has caused me a lot of grief.
> 
> --
> Dana DeLouis
> Windows XP
> Mathematica $VersionNumber -> 4.2
> ng_only at hotmail.com
> 
> = = = = = = = = = = = = = = = = =


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