Re: AW: about real part
- To: mathgroup at smc.vnet.net
- Subject: [mg41258] Re: AW: about real part
- From: "Dr. Wolfgang Hintze" <weh at snafu.de>
- Date: Sat, 10 May 2003 04:03:36 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Duanxiang Xu, I found some relevant information in the FAQ at: http://support.wolfram.com/mathematica/mathematics/algebra/realvariables.html For instance you find for the function Sqrt[]: In[1]:= ComplexExpand[Sqrt[a + b I], TargetFunctions -> {Re, Im}] Out[1]:= (a^2 + b^2)^(1/4)*Cos[ArcTan[a, b]/2] + I*(a^2 + b^2)^(1/4)*Sin[ArcTan[a, b]/2] as expexted. Play with other functions (Exp, Abs, Re, ...) to see how nice it works. Regards, Wolfgang Duanxiang Xu wrote: > Thank you for your information. > > Is that to say, there is no way to evaluate such kind > of expression? > > Regards, > Duanxiang > --- Matthias.Bode at oppenheim.de wrote: > >>Hello Duanxiang Xu, >> >>1."Re[z] gives the real part of the complex number >>z." >> >>2."Re[expr] is left unevaluated if expr is not a >>numeric quantity." >> >>Best regards, >>Matthias Bode >>Sal. Oppenheim jr. & Cie. KGaA >>Koenigsberger Strasse 29 >>D-60487 Frankfurt am Main >>GERMANY >>Tel.: +49(0)69 71 34 53 80 >>Mobile: +49(0)172 6 74 95 77 >>Fax: +49(0)69 71 34 95 380 >>E-mail: matthias.bode at oppenheim.de >>Internet: http://www.oppenheim.de >> >> >> >>-----Urspr眉ngliche Nachricht----- >>Von: Duanxiang Xu [mailto:duanxiangxu at yahoo.com] >>Gesendet: Dienstag, 6. Mai 2003 12:04 >>An: mathgroup at smc.vnet.net >>Betreff: about real part >> >> >>Hi, all >> >>I have problem when I was trying to get the real >>part >>of a complex expression, >>like >>Re[(Iwt+(L+1)LtD)^1/2] >>here w,L,D are real paramaters and t is real >>variable >>Mathematica seems could do nothing about this >> >>Anyone could help me? >> >>Thanks, >>Duanxiang >> >>__________________________________ >>Do you Yahoo!? >>The New Yahoo! Search - Faster. Easier. Bingo. >>http://search.yahoo.com >> > > > __________________________________ > Do you Yahoo!? > The New Yahoo! Search - Faster. Easier. Bingo. > http://search.yahoo.com > >