       Re: boolean variable with contours

• To: mathgroup at smc.vnet.net
• Subject: [mg110714] Re: boolean variable with contours
• From: Peter Pein <petsie at dordos.net>
• Date: Sat, 3 Jul 2010 08:17:21 -0400 (EDT)
• References: <201007011234.IAA18567@smc.vnet.net>

```Am Fri, 2 Jul 2010 06:54:31 +0000 (UTC)
schrieb maria giovanna dainotti <mariagiovannadainotti at yahoo.it>:

> Dear Math Group,
> I have the following problem when I do a contourplot I can't use
> the boolean variabile.  This is the function for which I would like
> to have the contours
>
> R1=1.029
> R2=2.92
> R3
> e1=300
> e2=1
> e3=100
> i=pi/12
>
> =C2 ContourPlot[]==0==Im[y,{x,-2,2 },{y,-20,20}]
>
>
> Thanks a lot for your help
> Maria

Hi Maria,

1.) pi is just any variable; I guess you want Pi (with capital P) and
the Re[] around  x/"real valued constant" is superfluous.
2.) what exactly do you expect from a call to Contourplot with three
expressions (not wrapped by a list). Did you want ParametricPlot3D
(which looks quite boring). Are the three expressions part of a vector
and you want the norm? That would lead to a few vertical stripes.
3.) It could speed thing up to throw FullSimplify once onto the
expression(s) to be plotted:
In:= R1=1029/1000;
R2=292/100;
R3;
e1=300;
e2=1;
e3=100;
i=Pi/12;
vec=FullSimplify[{
2*R3*Sin[ArcCos[Re[x/R3]]]*e3+2*R2/Cos[i]*Sin[ArcCos[Re[x/R2]]]*(e2-e3)+2*R=
1/Cos[i]*Sin[ArcCos[Re[x/R1]]]*(e1-e2),(2*R3*Sin[ArcCos[Re[x/R3]]]*e3+2*R2/=
Cos[i]*Sin[ArcCos[Re[x/R2]]]*(e2-e3))*(Boole[-R2<x<-R1]+Boole[R2>x>R1]),2*R=
3*Sin[ArcCos[Re[x/R3]]]*e3*(Boole[x<-R2]+Boole[x>R2])+R3*Cos[ArcSin[y/R3]]}=
,{x,y}\[Element]Reals]

Out= {200 Sqrt[400-x^2]+(299 Sqrt[1058841-1000000 x^2]-3960
Sqrt[5329-625 x^2])/(125 (Sqrt+Sqrt)),4/25 (1250 Sqrt[400-x^2]-99
Sqrt[(-2+Sqrt) (-5329+625 x^2)])
(Boole[73/25>x>1029/1000]+Boole[-(73/25)<x<-(1029/1000)]),Sqrt[400-y^2]+200
Sqrt[400-x^2] (Boole[25 x>73]+Boole[x<-(73/25)])}

Peter

P.S.: Claws-Mail opened this again; maybe I forgot to send it maybe
this posting comes twice. In the latter case: my apologies to the brave
moderator.

```

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