Re: Replacement
- To: mathgroup at smc.vnet.net
- Subject: [mg4422] Re: Replacement
- From: wagner at motel6.cs.colorado.edu (Dave Wagner)
- Date: Mon, 22 Jul 1996 00:09:22 -0400
- Organization: University of Colorado, Boulder
- Sender: owner-wri-mathgroup at wolfram.com
Whoops, in my previous post I gave the wrong output:
In article <4snbf1$rra at dragonfly.wolfram.com>,
Dave Wagner <wagner at motel6.cs.colorado.edu> wrote:
>In article <4shud7$g7n at ralph.vnet.net>,
>Sergej Gerassimov <ges at vsnhdd.cern.ch> wrote:
>>
>>x/Sqrt[a^2+b^2]+Sqrt[a^2+b^2]/y //. Sqrt[a^2+b^2]->r
>>gives:
>>
>> x r
>>------------- + -
>>Sqrt[a^2+b^2] y
>>
>>How to replace Sqrt[a^2+b^2] by r everywhere in the expression?
>
>A general solution to this type of problem is to introduce a dummy
>variable and use Solve:
>
> In[15]:=
> Solve[{dummy==x/Sqrt[a^2+b^2]+Sqrt[a^2+b^2]/y, r==Sqrt[a^2+b^2]},
> {dummy},{a,b}]
>
> Out[15]=
> x r
> ------------- + -
> 2 2 y
> Sqrt[a + b ]
That output should have been:
Out[1]=
x r
{{dummy -> - + -}}
r y
I was cutting and pasting all over the place and I must have inadvertently
included the wrong output in my post.
Sorry for any confusion.
Dave Wagner
Principia Consulting
(303) 786-8371
dbwagner at princon.com
http://www.princon.com/princon
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