need help with solve()



Maxima's solve command assumes that all symbols which are not being solved
for are independent arbitrary parameters.  Any equations constraining these
parameters therefore constitute an inconsistency.  Try, for example,
solve([x=a,a=1],[x]) vs. solve([x=a,a=1],[x,a]).

To solve your system, just use

      solve([U1,U2,U3,U4,U5],[V1,V2,V3,Z1,Z2]);

Maxima will give you "solutions" for Z1 and Z2 straight from your input, but
that's OK....

             -s

On 6/11/07, Ilan Barak <IlanB at raysat.com> wrote:
>
>
> I am a newbie to Maxima,
> Please help me solve this set of equations, resulting from an AC KCL
> problem
>
> U1: Z1=RR1+1/(S*CC1);
> U2: Z2=RR2+1/(S*CC2);
> U3: V1=(I1-(V1-V2)/RR3)*(Z1+Z2)/(Z1*Z2);
> U4: V2=((V1-V2)/RR3-(V2-V3)/RR4)/(S*CC3);
> U5: V3=(V2-V3)/RR4/(S*CC4);
> solve([U1,U2,U3,U4,U5],[V1,V2,V3]);
>
> I am interested in finding V3=F(RR1,RR2,RR3,RR4,CC1,CC2,CC3,CC4,S)
>
> I get the following:
>                                     1
> (%o2)             Z1 = ----- + RR1
>                                   CC1 S
> (%i3)
>                               1
> (%o3)           Z2 = ----- + RR2
>                              CC2 S
> (%i4)
>                                     V1 - V2
>                               (I1 - -------) (Z2 + Z1)
>                                       RR3
> (%o4)           V1 = ------------------------
>                                        Z1 Z2
> (%i5)
>                                  V1 - V2   V2 - V3
>                                  ------- - -------
>                                    RR3       RR4
> (%o5)             V2 = -----------------
>                                        CC3 S
> (%i6)
>                                       V2 - V3
> (%o6)                   V3 = ---------
>                                      CC4 RR4 S
>
> (%i7)
> Inconsistent equations:  (1 2)
> -- an error.  Quitting.  To debug this try debugmode(true);
>
>
> What am I doing wrong?
>
> Thanks
>
> Ilan
>
>
>
>
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