Dear all, I was working with ginsh and the following happened

a = 1 + x - x^2; 1+x-x^2 b = (1+sqrt(5))/2; 1/2+1/2*sqrt(5) subs(a,x==b); 3/2-(1/2+1/2*sqrt(5))^2+1/2*sqrt(5) expand(%); 5/4-1/4*5 expand(%); 5/4-1/4*5

The same thing also happens if you say

a = x^2 - x - 1;

Alessandro Zaccagnini %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Dr. Alessandro Zaccagnini Dipartimento di Matematica Universita' degli Studi di Parma Via Massimo d'Azeglio 85/A 43100 Parma Italia Telefono 0521 032302 (diretto/direct) 0521 032300 (centralino/operator) Telefax 0521 032350 e-mail zaccagnini@prmat.math.unipr.it alessandro.zaccagnini@unipr.it url http://www.math.unipr.it/~zaccagni/home.html