
Re: Automatic solving of unprepared polynomial equation systems?
Posted:
Mar 31, 2013 7:11 PM


Am 31.03.2013 16:15, schrieb IV: > Hallo, > > I'm not a mathematician. I'm a natural scientist. > > It seems that computer algebra systems like Maple (version 11) and > Mathematica (version 7) can not solve all simply solvable equation > systems automatically. Let us look e.g. at the equation system > [c1=A*B/C, c2=C*A/D, D=c3A, C=AB], where c1, c2 and c3 are real or > complex constants, A, B, C and D are real or complex variables, and the > solutions for the variable A are wanted. The equation system forms a > cubic equation in A, and the solutions of the equation system are the > solutions of this cubic equation. But the solve command can find neither > the cubic equation nor its solutions. .... Just for completeness:
to get the cubic equation for a in dependence of the ci, type into Mathematica: eqfora = Eliminate[{c1 == a b/c, c2 == c a/d, d == c3  a, c == a  b}, {b, c, d}]
to get (a + c1) c2 c3 == a (a^2 + a c2 + c1 c2)
Peter

