New user question



> I'm new to Maxima

Thanks for your interest in Maxima!

> f1: (Rb/Bmin) * B * (B - Bmin) * (1 - B/Bmax) - A * B * F = 0;
> f2: (Rf/Fmin) * F * (F - Fmin) * (1 - F/Fmax) - A * B * F = 0;
> res: solve ([f1, f2], [B, F]);
>
> Now if I input just that, and try to solve it symbolically,
> Maxima hangs.

I think you have found a bug.

Your system reduces to something of the form:

  q1: b2 * B^2 + b1 * B + b0 + bf * F = 0

  q2: f2 * F^2 + f1 * F + f0 + fb * B = 0

and Maxima seems to run forever on that, too.

I tried solving the system step by step.

First, I solved for F in f1 and substituted.  This leads to a quartic
mess.

Then I tried solving for B in f1 and substituting into f2; Solve solves
the resulting equation easily.  There are two non-trivial solutions in
each step, and you'll have to check which ones are meaningful.

By the way, it can be helpful to declare some facts about your
parameters, e.g.

assume(Bmax>B,B>Bmin,Bmin>0,
       Fmax>F,F>Fmin,Fmin>0,
       Rb>0,Rf>0,A>0)

This will keep some radicals "clean", though it does *not* use these
facts in Solve (for example, you will get the B=0, F=0 solution).

Good luck.

      -s