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.

\[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>

```

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