Can't bring Maxima to resolve reverse of a function



hi Matrin

it is a bug maxima solve system .
Generally speaking,at more than 3 degree none linear system
we can not solve algebraically even if it is solvable.
(see Richard E.Carndall:Projects in Scientific Computation
2.1.2 2~4)
But your problem must be algebraically solvable.
Maybe at older version,we could solve this??
We must fix this bug.
till that time,by hand,use subst. example
 
maxima <thisfile
-------------------------------------------
writefile("log0220.9");
a1: z^2 = x^2+y^2;
a2: (z+211.71141889735)^2 = (2000-x)^2+y^2;
a3: (z+727.71950507539)^2 = (5000-x)^2+(y-1000)^2;

b1: ratsimp(a2-a1);
b2: ratsimp(a3-a1);

b3: solve([b1,b2],[x,y]);
solve(subst(b3[1],a1),z);
%,numer;
subst(%[2],b3[1]);

closefile();
quit();
------------------------------------------------
thanks

Gosei Furuya (go_furuya@neuro.co.jp)

.