Re: Taking the Arg of a complex number
- To: undisclosed-recipients:;
- Subject: [mg122106] Re: Taking the Arg of a complex number
- From: Alexei Boulbitch <Alexei.Boulbitch at iee.lu>
- Date: Fri, 14 Oct 2011 05:53:47 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
Here ComplexExpand should help. Try this: (* This is youe expression*) x=Exp[I*\[CurlyPhi]] E^(I \[CurlyPhi]) (* This is the answer *) y=ComplexExpand[Arg@x] ArcTan[Cos[\[CurlyPhi]],Sin[\[CurlyPhi]]] (* Let us check, if it returns an expected result *) y/.\[CurlyPhi]->\[Pi]/4 \[Pi]/4 Have fun. Would appreciate any help here, endless Googling has not revealed the answer to me: If I define a complex number symbolically, such as x = A Exp[I phi], why does Arg[x] never return the answer I expect, phi? Using Refine with the as sumptions phi is real and between 0 and 2 pi, and that A is greater than 0 doesn't seem to help. All I get is Arg[Exp[I phi]] Alexei BOULBITCH, Dr., habil. IEE S.A. ZAE Weiergewan, 11, rue Edmond Reuter, L-5326 Contern, LUXEMBOURG Office phone : +352-2454-2566 Office fax: +352-2454-3566 mobile phone: +49 151 52 40 66 44 e-mail: alexei.boulbitch at iee.lu<mailto:alexei.boulbitch at iee.lu>