#3863: numerical integration of x^2.7 * e^(-2.4*x) fails
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Reporter: ddrake | Owner: gfurnish
Type: defect | Status: new
Priority: major | Milestone: sage-4.0.1
Component: calculus | Keywords: integration integral calculus symbolic
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Comment(by ddrake):
Replying to [comment:2 kcrisman]:
> The essential problem is that with half-integer or integer exponents of
x, Maxima can symbolically integrate this using Erf. Otherwise it can't
(that doesn't mean it's not possible, just that Maxima doesn't know).
Before, Sage tried to turn the expression into a complex one if it
couldn't evaluate it, but that doesn't do much for a real (unevaluated)
integral; now the new symbolics just complain that it's not numeric, which
of course it isn't.
Ah, that makes sense. I don't mind that just naively running {{{.n()}}}
doesn't work; we could have, like Mathematica, some sort of
numerical_integrate that would try to evaluate the integral, and then punt
to something like Simpson's rule to just estimate it. I'm sure, though,
that there's vastly better ways to actually do numerical integrals than
just a plain vanilla Calculus 1 application of Simpson's Rule.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/3863#comment:3>
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