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Re: Circle equation problem

  • To: mathgroup at smc.vnet.net
  • Subject: [mg61580] Re: Circle equation problem
  • From: Daniele Lupo <danwolf80_no_spam_ at libero.it>
  • Date: Sat, 22 Oct 2005 05:11:26 -0400 (EDT)
  • References: <dja2c3$fig$1@smc.vnet.net> <djcg72$6ci$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Il Sat, 22 Oct 2005 04:46:26 +0000 (UTC), Jens-Peer Kuska ha scritto:

> expr = Abs[p]^2 == Abs[(G - X + I*Y)/(-1 + G*(X + 
> I*Y))]^2;
> 
> expr1 = ComplexExpand[expr, TargetFunctions -> 
> {Re, Im}] // FullSimplify;
> 
> expr2 = (Expand /@ (expr1 /. a_ == b_/c_ :> a*c == 
> b)) /.
> a_ == b_ :> a - b == 0
> 
> and you see that at least X must be scaled by 
> x->X/(p*G)
> 

Hi.

It does not work. As I've said, G and p are complex parameters, so I must
to write, for expr1

expr1 = ComplexExpand[expr, {p, G}, TargetFunctions -> {
      Re, Im}] // FullSimplify

Then, using your command for expr2, I see X and Y that are present in the
denominator, so the problem it's not resolved...

Daniele Lupo


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