On Aug 22, 2:23 pm, Oscar Gerardo Lazo Arjona <[email protected]> wrote:
> sage: a=8594.0*x^3 - 30768.0 *x^2 + 36399.0 *x -14224.0 > sage: b=solve(a==0,x) > sage: for i in b: > ....: c=i.rhs() > ....: print c.n() > ....: > 1.19783952189420 - 4.16333634234434e-17*I > 0.998467807920659 + 1.38777878078145e-17*I > 1.38386488335712 + 2.08166817117217e-17*I IIRC Sage solve punts to Maxima solve, which tries to find an exact solution. In Maxima I get [x = (-sqrt(3)*%i/2-1/2)*(sqrt(5159598107)*%i/ (18464209*2^(3/2))-6552490/79340706073)^(1/3) +457267*(sqrt(3)*%i/2-1/2)/(36928418*(sqrt(5159598107)*%i/ (18464209*2^(3/2))-6552490/79340706073)^(1/3))+5128/4297, x = (sqrt(3)*%i/2-1/2)*(sqrt(5159598107)*%i/ (18464209*2^(3/2))-6552490/79340706073)^(1/3) +457267*(-sqrt(3)*%i/2-1/2)/(36928418*(sqrt(5159598107)*%i/ (18464209*2^(3/2))-6552490/79340706073)^(1/3))+5128/4297, x = (sqrt(5159598107)*%i/ (18464209*2^(3/2))-6552490/79340706073)^(1/3) +457267/(36928418*(sqrt(5159598107)*%i/ (18464209*2^(3/2))-6552490/79340706073)^(1/3))+5128/4297] Now it's easy to see that these must all be real, so essentially there must be an identity here (to make the imaginary units go away) which is not being exploited by Maxima. If you are specifically looking for numerical values, probably there is a way to invoke a different algorithm in Sage. FWIW Robert Dodier -- To post to this group, send an email to [email protected] To unsubscribe from this group, send an email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
