Question on ComplexExpand

*To*: mathgroup at smc.vnet.net*Subject*: [mg51129] Question on ComplexExpand*From*: carlos at colorado.edu (Carlos Felippa)*Date*: Tue, 5 Oct 2004 04:37:26 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

This question is related to a previous post, and to a project in stability of a G&C feedback system I am working on. Is there a way to get ComplexExpand to automatically convert Abs to Sqrt, Arg to ArcTan, etc., as target functions? For example ComplexExpand[Abs[x+y*I]] gives Sqrt[x^2+y^2] ComplexExpand[Arg[x+y*I]] gives ArcTan[y/x] (Note: ComplexExpand assumes all symbols are real by default.) I wasnt able to find an option to do that in 4.2.1. Thanks.

**Follow-Ups**:**Re: Question on ComplexExpand***From:*Andrzej Kozlowski <akoz@mimuw.edu.pl>