Re: integrate a sum using Mathematica
- To: mathgroup at smc.vnet.net
- Subject: [mg123729] Re: integrate a sum using Mathematica
- From: Alexei Boulbitch <Alexei.Boulbitch at iee.lu>
- Date: Fri, 16 Dec 2011 05:54:57 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
How can I integrate a sum using Mathematica
> eg polyIntegrate[Sum[f[x_[[i]]],{i,1,n}],{x[[i]],0,infinty}]
> am new in using Mathematica ,,,i have version 7
Why not? The syntax is a bit different. For example,
This is a sum (for this example I have chosen the one that will be
then certainly integrated):
sum[x] :=
Sum[x^i Exp[-x], {i, 0, n},
Assumptions -> {n \[Element] Integers && n > 0}]
sum[x]
(E^-x (-1 + x^(1 + n)))/(-1 + x)
And this is the integral:
Integrate[sum[x], {x, 0, Infinity},
Assumptions -> {n \[Element] Integers && n > 0}]
(I \[Pi] + ExpIntegralEi[1])/E -
E^(-I n \[Pi]) Gamma[2 + n] Subfactorial[-2 - n]
I did it in the last version, but I do not expect anything wrong also
in the 7th version.
Have fun, Alexei
Alexei BOULBITCH, Dr., habil.
IEE S.A.
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