Re: Simplify expression

*To*: mathgroup at smc.vnet.net*Subject*: [mg57804] Re: Simplify expression*From*: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>*Date*: Thu, 9 Jun 2005 05:17:36 -0400 (EDT)*Organization*: Uni Leipzig*References*: <d8697g$c9t$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Hi, you can't because Sqrt[[(x1^2-x2^2)^2] is Abs[x1^2-x2^2] Regards Jens "Mukhtar Bekkali" <mbekkali at gmail.com> schrieb im Newsbeitrag news:d8697g$c9t$1 at smc.vnet.net... >I need to solve system of equations >f1[x1,x2]=0,f2[x1,x2]==0, however, > some elements of these equation have the form > Sqrt[(x1^2-x2^2)^2]. It > takes really long time to solve. If, however, I > manually simplify > those elements, for example, > Sqrt[(x1^2-x2^2)^2]=x1^2-x2^2 then solve > is fast. Therefore, the question is how I can > force mathematica > simplify expressions of this sort (another > elements are fractions that > depend on x1 and x2 in Mathematica's mind but in > reality they cancel > out and fraction becomes a number). I do not > want to use FindRoot since > I want to see all solutions. Thanks, Mukhtar > Bekkali >