-----Original Message-----
From: Gosse michel
Sent: Friday, December 10, 2010 4:48 PM
To: Liste maxima
Subject: solving a system
Hello
With :
(%i1) f(x):=a+k/(x-b);
e1:f(-2)=-1;
e2:f(1)=-1;
e3:f(2)=5/2;
solve([e1,e2,e3],[a,b,k]);
(%o1) f(x):=a+k/(x-b)
(%o2) k/(-b-2)+a=-1
(%o3) k/(1-b)+a=-1
(%o4) k/(2-b)+a=5/2
(%o5) [[a=-1,b=2,k=0]]
it seems it's a bug, because f(x)=-1 is clearly not a solution.
The solution is good with f(-2)=1
Maxima 5.20.1
I get
solve([e1,e2,e3],[a,b,k]);
[[a = - 1, b = 2, k = 0]]
[a,b,k]:map('rhs, first(%));
[- 1, 2, 0]
f(-1);
- 1
So f(x) = -1 is a solution.
Rich