Thanks for helping. I am trying to compute (not numericaly!) the roots of a quadratic equation build from lagrange_polynomial()...
sage: p2 = SR(-3/4*pi)*x^2 + SR(7/4*pi)*x sage: p2.roots(x) [(7/3, 1), (0, 1)] Now we are back to the original question: Why the following rise a type error?? I guess that the problem comes from the type of p1, not being an Expression. So is it possible to cast this p1 to the Expression class? sage: SR(-3/4*pi)*x^2 + SR(7/4*pi)*x sage: basering = PolynomialRing(SR, 'x') sage: p1 = basering.lagrange_polynomial([(0,0), (1,pi), (2, pi/2)]) sage: p1 -3/4*pi*x^2 + 7/4*pi*x sage: p1.roots(x) (...) TypeError Traceback (most recent call last) (...) TypeError: base_ring must be a ring -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
