Re: symbolic complex expressions

*To*: mathgroup at smc.vnet.net*Subject*: [mg53667] Re: [mg53637] symbolic complex expressions*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Sat, 22 Jan 2005 03:51:49 -0500 (EST)*Organization*: Mathematics & Statistics, Univ. of Mass./Amherst*References*: <200501211135.GAA01324@smc.vnet.net>*Reply-to*: murray at math.umass.edu*Sender*: owner-wri-mathgroup at wolfram.com

ComplexExpand[Abs[x + I y]] ComplexExpand[x/(x + I y)] Frank wrote: > Hi, > > I've 2 question with mathematica using symbolic complex expressions. > > - Is there a possibility to make from i.e. |x + I y| -> sprt(x^2+y^2) > if x and y are Real. Abs[] doesn't work? > > > - You've a fraction like this x/(x + I y) and you want to eliminate > the complex expression in the denominator. > i.e. doing something like this: x/(x + Iy)*(x - I y)/(x - I y) -> (x^2 > - I x y)/(x^2+y^2) > > How do you do this with mathematica? > > Thanks, > > Frank > > -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305

**References**:**symbolic complex expressions***From:*frankdeicke@gmx.de (Frank)