algsys([a*b=c*d],[a,b,c,d])
returns
[[a = %R2*%R3/%R1,b = %R1,C = %R2,d = %R3]]
This is missing some of the solutions where one or both
of a and b is zero and one or both of c and d is zero.
The complete list of these solutions is:
[[a=0,b=%r1,c=0,d=%r2],
[a=0,b=%r3,c=%r4,d=0],
[a=%r5,b=0,c=0,d=%r6],
[a=%r7,b=0,c=%r8,d=0]]
The first two are subsumed by the original solution as
long as b # 0.
Robert Dodier
2006-07-08
Robert Dodier
2006-09-09