-----Michel Gosse wrote: -----
>Solving the above system with algsys, i obtain
>only complex solutions. How can
>i obtain the real solutions of this system ?
>
>eq1: alpha * beta * teta / ( (alpha-1)*(beta+1)) - 1.5
>eq2: alpha * beta * teta^2 / ( (alpha-2)*(beta+2)) - 3
>eq3: alpha * beta * teta^3 / ( (alpha-3)*(beta+3)) - 4.5
To find only the real solutions, set the option variable
'realonly' to true. Also, the user documentation says that
algsys solves polynomial equations, so I mapped ratnumer
over your equations to covert them to polynomial form:
(%i33) algsys(map('ratnumer, [eq1,eq2,eq3]),[alpha,beta,teta]), realonly :
true;
`rat' replaced -1.5 by -3//2 = -1.5
`rat' replaced -4.5 by -9//2 = -4.5
(%o33) []
The fact that algsys returns the empty list doesn't prove that there
are no real solutions. Maxima might be correct, but it might be wrong.
Do you have some reason to think that there is a real solution?
Barton