Hi, two things

1. Maxima cannot  evaluate limit of primitive function at infinity:
'limit(6*li[4](%e^x)-6*x*li[3](%e^x)+3*x^2*li[2](%e^x)+x^3*log(1-%e^x)-
x^4/4,x,inf)

2. Sage does not understand the function li[4](exp(x))
http://maxima.sourceforge.net/docs/manual/en/maxima_14.html#Item_003a-li

sage: maxima('li[1](x)').sage()
-log(-x + 1)

sage: maxima('li[2](x)').sage()
polylog2(x)

sage: maxima('li[3](x)').sage()
polylog3(x)

sage: maxima('li[4](x)').sage()
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call
last)
......
TypeError: unable to make sense of Maxima expression 'li[4](x)' in
Sage


Back to the integral:
-------------------------

Wolframalpha returns numerical approximation only

Maple returns pi^4/(15)

in Sage:
----------------------------------------------------------------------
| Sage Version 4.3.3, Release Date: 2010-02-21                       |
| Type notebook() for the GUI, and license() for information.        |
----------------------------------------------------------------------
sage: numerical_integral(x^3/(exp(x)-1),0,Infinity)
(6.4939394075015517, 2.7073822124476823e-06)
sage: (pi^4/15).n()
6.49393940226683



Robert


On 6 bře, 18:42, Oscar Gerardo Lazo Arjona <[email protected]>
wrote:
> Hey guys, what's wront with this integral?
>
> sage: integral(x^3/(e^x-1),x,0,oo)

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