On 2015-03-10, Dima Pasechnik <[email protected]> wrote: > On 2015-03-10, M M <[email protected]> wrote: >> I get different results from Sage when I try to get a numerical >> approximation for an expression and if I use evaluate a preparse of the >> string. I get different results on different versions of sage as well. Here >> are samples: > > Integration is done by Maxima, and it is a bloody mess; e.g. > (with Sage 6.6.beta3) > > sage: numerical_integral(x/(x^3-x+1.), 1., 2.) > (0.565799916456428, 6.281640945809164e-15) > sage: integral(x/(x^3-x+1), x, 1, 2).n() > 1.11396858782562 > sage: integral(x/(x^3-x+1), x, 1, 2).full_simplify().n() > 0.168522351678247 > sage: > > Do you know which one is actually correct? > It looks like the 2nd one might be right (by looking at > sage: plot(x/(x^3-x+1), x, 1, 2))
sorry, the 1st looks right (the plot is not from 0 to 2, but from 1 to 2, so the value looks a bit above 1/2). (and Wolfram Alpha outputs 0.5658) -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
