Re: Circle equation problem

• To: mathgroup at smc.vnet.net
• Subject: [mg61640] Re: Circle equation problem
• From: "Valeri Astanoff" <astanoff at yahoo.fr>
• Date: Mon, 24 Oct 2005 21:06:58 -0400 (EDT)
• References: <dja2c3\$fig\$1@smc.vnet.net><djcgsv\$6ka\$1@smc.vnet.net> <djfmel\$amv\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Daniele,

You're right.
One has to use SolveAlways instead of Solve :

In[1]:=
eq=Abs[p] == Abs[(G - X + I*Y)/(-1 + G*(X + I*Y))];
e1 = List@@eq ;
e2 = ComplexExpand[e1,{p,G}] ;
e3 = e2 ^2;
e4 = e3[[1]]-e3[[2]];
e5 = Numerator[e4//Together] ;
cir = (X-XCenter)^2+(Y-YCenter)^2-ray^2 ;
ce = CoefficientList[e5,{X,Y}]//Flatten;
cc = CoefficientList[cir,{X,Y}]//Flatten;

In[2]:=
{ray, XCenter, YCenter} /. sol /. G -> (.7 - .25 I) /. p -> (.8 + .9I)

Out[2]=
{{-0.45675, 0.315, -0.424365},
{-0.45675, 0.315, 0.424365},
{0.45675, 0.315, -0.424365},
{0.45675, 0.315, 0.424365}}

hth

v.a.

```

• Prev by Date: Re: Running the kernel command line with additional input files
• Next by Date: Re: Running the kernel command line with additional input files
• Previous by thread: Re: Circle equation problem