Why does this not work: sage: K.<t> = PowerSeriesRing(QQ, 't', 5) sage: R.<y> = K[] sage: F = y^2 + y - 2*t - 3*t^2 - t^3 sage: F.discriminant().sqrt() 1 + 4*t - 2*t^2 + 10*t^3 - 42*t^4 + O(t^5)
but sage: F.roots() --------------------------------------------------------------------------- TypeError Traceback (most recent call last) ... TypeError: unable to convert Ideal (-2*t - 3*t^2 - t^3, 1, 1) of Power Series Ring in t over Rational Field to a rational while the quadratic formula works as it should: sage: D = F.discriminant() sage: sol = (-F[1]+D.sqrt())/(2*F[0]) sage: F(sol) -4*t + 6*t^2 - 38*t^3 + O(t^4) John -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
