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Simplify Question

  • To: mathgroup at smc.vnet.net
  • Subject: [mg41633] Simplify Question
  • From: "Dana DeLouis" <delouis at bellsouth.net>
  • Date: Thu, 29 May 2003 08:14:00 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

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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