Re: Question on ComplexExpand
- To: mathgroup at smc.vnet.net
- Subject: [mg51137] Re: [mg51129] Question on ComplexExpand
- From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
- Date: Wed, 6 Oct 2004 04:34:09 -0400 (EDT)
- References: <200410050837.EAA08439@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
On 5 Oct 2004, at 17:37, Carlos Felippa wrote:
> *This message was transferred with a trial version of CommuniGate(tm)
> Pro*
> 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.
>
ComplexExpand[Abs[x + y*I], TargetFunctions -> {Re, Im}]
Sqrt[x^2 + y^2]
ComplexExpand[Arg[x + y*I], TargetFunctions -> {Re, Im}]
ArcTan[x, y]
Andrzej Kozlowski
Chiba, Japan
http://www.akikoz.net/~andrzej/
http://www.mimuw.edu.pl/~akoz/
- References:
- Question on ComplexExpand
- From: carlos@colorado.edu (Carlos Felippa)
- Question on ComplexExpand