I'm running Sage 9.0 on a Windows 10 machine.
I get the same incorrect series from the built-in sin_integral function,
so the problem is not the integration.
sage: taylor(sin_integral(x),x,0,10)
73/466560*x^9 - 127/35280*x^7 + 31/600*x^5 - 7/18*x^3 + x
Fernando
On 9/29/2020 3:36 AM, Emmanuel Charpentier wrote:
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
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