Re: Expanding a Square Root
- To: mathgroup at smc.vnet.net
- Subject: [mg50820] Re: [mg50813] Expanding a Square Root
- From: Andrzej Kozlowski <andrzej at akikoz.net>
- Date: Wed, 22 Sep 2004 02:27:37 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
On 22 Sep 2004, at 13:11, Jim Dars wrote: > Hi All, > > I should point out that I use Mathematica 4.0 infrequently, thus I may > be > missing the obvious. My problem is as follows: > > In the following I use the square root sign from the palette for SQRT > Expand[(44+9*SQRT(23))^2] yields > 3799 + 792*SQRT(23) > > I now wish to take the square root of 3799 + 792*SQRT(23) to return > to my > original expression. However > > Expand[SQRT(3799 + 792*SQRT(23))] merely yields > > [SQRT(3799 + 792*SQRT(23))] > > What is the proper command to make SQRT(3799 + 792*SQRT(23)) yield > 44+9*SQRT(23) > > Best wishes, Jim > > > RootReduce[Sqrt[3799 + 792*Sqrt[23]]] 44 + 9*Sqrt[23] You can of course also use FullSimplify instead of RootReduce but FullSimplify just calls RootReduce to do the job. Andrzej Kozlowski Chiba, Japan http://www.akikoz.net/~andrzej/ http://www.mimuw.edu.pl/~akoz/