Unexpected bahaviour



Mein Linuxrechner Arbeit wrote:
>
> Hello,
> I tried to replase a in eq11 by the expression on the right side of 
> "=". [a=-(w2-w1)/(2*d*p-2*d*m-d^2)]
> Bit instead of doing that, s is simply replaced by a.
> How can I make maxima do what I want?
>
> (%i1) eq10: w1-w2=-a*(p-d-m)^2 + a*(p-m)^2;
> (%i2) eq11: w3-w1=-s*(p+d-m)^2 + s*(p-m)^2;
> (%i3) linsolve(eq10,[a]);
> (%i4) eq11: subst(a,s,eq11);
I would use an intermediate variable s to store the solution, but % 
would work too.

(%i1) eq10: w1-w2=-a*(p-d-m)^2 + a*(p-m)^2$
(%i2) eq11: w3-w1=-s*(p+d-m)^2 + s*(p-m)^2$
(%i3) s:solve(eq10,[a]);
                                      w2 - w1
(%o3)                     [a = - ------------------]
                                                  2
                                 2 d p - 2 d m - d
(%i4) subst(s,eq11);
                                      2                2
(%o4)                w3 - w1 = (p - m)  s - (p - m + d)  s