Re: a question about complex variable

*To*: mathgroup at smc.vnet.net*Subject*: [mg21673] Re: a question about complex variable*From*: "Robert Nowak" <robert.nowak at ims.co.at>*Date*: Sat, 22 Jan 2000 02:52:27 -0500 (EST)*Organization*: telecom.at (Vienna, Austria)*References*: <200001170343.WAA13446@smc.vnet.net> <8615hh$jtk@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Hello, try the following: Abs[(-I Cos[2 P] - Sin[2 P]) Tan[A]]//FullSimplify[#, Element[P, Reals]] & but for the Arg[] I am sorry .... Regards Robert -- --- Robert Nowak (robert.nowak at ims.co.at) Ionen Mikrofabrikations Systeme GmbH A-1020 Wien, Schreygasse 3, Austria Phone: (+43 1)2144894-32, Fax: (+43 1)2144894-99 ZHU Xiaopeng <xpzhu at red.semi.ac.cn> wrote in message news:8615hh$jtk at smc.vnet.net... > In my algebra computation, I obtain a expression: > C = (- I Cos[2 P] - Sin[2 P]) Tan[A] > P,A are real variables. Apperently, the argument of C is -2(P+Pi/4) and the > absolute value of C is Tan[A]. But when I use Arg[C] and Abs[C], Mathematica > tells me: > > Out[41]=Abs[(-I Cos[2 P] - Sin[2 P]) Tan[A]]// FullSimplify[#, {a, P} \[Element] Reals] & > Out[42]=Arg[(-I Cos[2 P] - Sin[2 P]) Tan[A]]// FullSimplify[#, {a, P} \[Element] Reals] & > > This problem appeared at beginning of the computation. I have no idea to deal > with it, so the expressions become longer and longer during the computation. > Can somebody help me? > >

**References**:**Re: Plotting A verticle line?***From:*BobHanlon@aol.com