Re: sqrt[x^2]
- To: mathgroup at smc.vnet.net
- Subject: [mg9779] Re: sqrt[x^2]
- From: hans.steffani at e-technik.tu-chemnitz.de (Hans Steffani)
- Date: Fri, 28 Nov 1997 05:34:57 -0500
- Organization: University of Technology Chemnitz, FRG
- Sender: owner-wri-mathgroup at wolfram.com
Zen at archer.com (ZenArcher) writes: >Well I know this is really elementary, but I just don't understand this >result: >sqrt[x^2]=sqrt[x^2] >sqrt[4^2]=4 >Why doesn't Mathematica tell me that the Square Root of x^2 is x, but it This is because Sqrt[x^2] is not always x. Take x=-2 as an example where Sqrt[(-2)^2] evaluates to 2. >will tell me that the square root of 4^2 is 4? Because that's correct. Maybe you look for PowerExpand[] but than you have to know what you are doing to avoid wrong results. h.f.s. [fup,cc] -- Hans Friedrich Steffani Institut fuer Elektrische Maschinen und Antriebe, TU Chemnitz mailto:hans.steffani at e-technik.tu-chemnitz.de http://www.tu-chemnitz.de/~hfst/