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Re: Solving Equations with 3 variables and many parameters

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  • Subject: [mg132384] Re: Solving Equations with 3 variables and many parameters
  • From: Murray Eisenberg <murray at math.umass.edu>
  • Date: Sun, 2 Mar 2014 21:27:54 -0500 (EST)
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Neither the first expression where you claim that Solve worked nor the 
second where you said "It doesn't understand how to interpret the word 
'Solve'" cannot be evaluated because you have the same error in each: 
the single equal sign (an abbreviation for Set, i.e., assign a value) 
needs to be a double equal sign. One uses the double equal sign for 
forming equations.

I don't even know what you mean when you say that "It doesn't understand 
how to interpret the word 'Solve'". In each case, before the correction, 
you'll get an Infinite Recursion error message.

With that correction, both will work just fine.

On Mar 2, 2014, at 1:04 AM, drascher <rascher at usfca.edu> wrote:

> Hello,
>
> I am able to get Mathematica to solve:
>
> Solve[{P1=(a[1]+C*b[11]+b[12]*P2)/(2*b[11]), P2=(a[2]+C*b[22]+b[21]*P1)/(2*b[22])}, {P1, P2}]
>
> but it won't solve the following (which is one more variable P3 and its equation):
>
> Solve[{P1=(a[1]+C*b[11]+b[12]*P2+b[13]*P3)/(2*b[11]), P2=(a[2]+C*b[22]+b[21]*P1+b[23]*P3)/(2*b[22]), P3=(a[3]+C*b[33]+b[31]*P1+b[32]*P2)/(2*b[33])}, {P1, P2, P3}]
>
> It says that it doesn't understand how to interpret the word "Solve" even though it does it for the first eqn.
>
> Any help is appreciated.
>


Murray Eisenberg                                murray at math.umass.edu
Mathematics & Statistics Dept.      
Lederle Graduate Research Tower      phone 240 246-7240 (H)
University of Massachusetts               
710 North Pleasant Street                
Amherst, MA 01003-9305









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