Hello, On Thu, Mar 5, 2009 at 11:24 AM, Bob <gotw...@gmail.com> wrote: > > I need to find the roots of this polynomial, where are coefficients > are in this matrix: > > coef=matrix([[1],[-1],[-1],[0]])
First, you should construct a polynomial. A matrix of coefficients is not the preferred way to work with polynomials in Sage. sage: coef=matrix([[1],[-1],[-1],[0]]) sage: R.<x> = QQ[]; R sage: f = R( list(coef.column(0)) ); f -x^2 - x + 1 Above, I created the polynomial ring R (in the variable x), and then I created the polynomial by passing in the 0th column of the matrix in as a list. Next, you use the .roots() method to get the roots. If you don't specify an additional ring, it will default to the one that the polynomial is defined over. sage: f.roots() [] sage: f.roots(QQ) [] The above says that the polynomial has no rational roots. You probably want floating point complex numbers (which is what polyroots in MathCAD gives). sage: CDF Complex Double Field sage: f.roots(CDF) [(-1.61803398875, 1), (0.61803398875, 1)] --Mike --~--~---------~--~----~------------~-------~--~----~ 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 URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
