restart; g:=x->(x^2-5+alpha*x)/alpha; #g:=x->(1/2)*(x+5/x); alpha:=-3; x0:=1.0; x1:=g(x0); x2:=g(x1); x3:=g(x2); x4:=g(x3); x5:=g(x4); x6:=g(x5); A:=(t4,t5,t6)->t4-(t5-t4)^2/(t6-2*t5+t4); x7:=A(x4,x5,x6); sqrt(5.0); x8:=g(x7); x9:=g(x8); A(x7,x8,x9);