I can’t reproduce your problem :
sage: sage.version.version
'9.2.beta13'
sage: var('t')
t
sage: assume(x>0)
sage: f(x)=integrate(sin(t)/t,t,0,x)
sage: f
x |--> sin_integral(x)
sage: taylor(f(x),x,0,10)
1/3265920*x^9 - 1/35280*x^7 + 1/600*x^5 - 1/18*x^3 + x
My platform is Debian testing running on core i7 + 16 GB RAM ; sage is
built to use as much system packages as possible. hat are your platforms ?
HTH,
Le lundi 28 septembre 2020 à 22:03:56 UTC+2, fqgo...@colby.edu a écrit :
> I am trying to see how to do a standard calculus exercise in Sage. I want
> a power series for the integral of sin(x)/x. I tried:
>
> sage: var('t')
> t
> sage: assume(x>0)
> sage: f(x)=integrate(sin(t)/t,t,0,x)
> sage: f
> x |--> sin_integral(x)
> sage: taylor(f(x),x,0,10)
> 73/466560*x^9 - 127/35280*x^7 + 31/600*x^5 - 7/18*x^3 + x
>
> The first weirdness is that Sage can't compute the integral unless I add
> the "assume(x>0)"; I'm not sure why.
>
> The second weirdness is that the Taylor series is wrong!
> Taylor(Si(x),x,0,10) gives the same answer.
>
> Fernando
>
>
> --
> ==================================================================
> Fernando Q. Gouvea
> Carter Professor of Mathematics
> Colby College
> Mayflower Hill 5836
> Waterville, ME 04901 fqgo...@colby.edu
> http://www.colby.edu/~fqgouvea
>
> The object of opening the mind, as of opening the mouth, is to shut it
> again on something solid.
> -- G. K. Chesterton, Autobiography.
>
>
>
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