Re: plotting

*To*: mathgroup at smc.vnet.net*Subject*: [mg124880] Re: plotting*From*: Alexei Boulbitch <Alexei.Boulbitch at iee.lu>*Date*: Fri, 10 Feb 2012 05:56:46 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

Dear All, I'm trying to plot the function r[x] as a function of x (x==CF?/=CF?0) but when I put values for x couldn't get number. rewrite This is kindly ask you for your comments on how to plot r[x] as a function of x. Thank you in advance for your help. :) \[Gamma]m = 10^11; \[Gamma]e = 2.73*10^13; \[Omega]e = 1.37*10^16; \[Omega]m = 0.5 \[Omega]e; \[Omega]0 = 0.4092 \[Omega]e; \[Kappa]0 = 10^4; x[\[Omega]_] := \[Omega]/\[Omega]e y1 = 1.971*10^-3; y2 = 0.23*10^-5; a := 1 - 1/(x[\[Omega]]^2 + y1^2) b := \[Gamma]e/(\[Omega]e * x[\[Omega]] (x[\[Omega]]^2 + y1^2)) c := 1 - (\[Omega]m^2/\[Omega]e^2)/(x[\[Omega]]^2 + y2^2) d := (\[Omega]m^2/\[Omega]e^2*\[Gamma]m)/(\[Omega]e* x[\[Omega]] (x[\[Omega]]^2 + y2^2)) r[x_] := \[Sqrt]((\[Omega]e^2*x[\[Omega]]^2)/( 9*10^16 (a^2 - b^2 - 1.69) + 4 a^2*b^2 ) (1.3 (a^2 - b^2) - 1.69 (a*c - b*d))*(a^2 - b^2 - 1.69) + ((2.6 a*b - 1.69 (a*d + b*c)) 2 a*b)) Plot[r[x]/\[Kappa]0, {x, 0, 0.6}] Your problem is that you did not define Omega. It is present in your definition of r in a hidden from in many places (for example, through the definitions of a, b , c and d, let alone x). Then the definition of r[x_] is misleading. You should better define r[Omega] instead, as well as a[Omega] instead of a and so on. After you redefine it better, check if r is real. I tried to redefine your functions and have got complex valued r. This might be, however, because in redefinition I changed you initial intention. Have fun, Alexei 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>