Martin R wrote:
>
> Hi integration gurus!
>
> It seems to me that the integral of log(x)^(-t-1) is possibly incorrect:
>
> (6) -> f := log(x)^(-t)
>
> - t
> (6) log(x)
> Type:
> Expression(Integer)
> (7) -> r := integrate(f, x)
>
> (7) cos(%pi t)Gamma(- t + 1,- log(x))
> Type:
> Union(Expression(Integer),...)
> (8) -> D(r, x) - f
>
> - t - t
> (8) - log(x) + cos(%pi t)(- log(x))
> Type:
> Expression(Integer)
Yes. Internally (as shown by ")trace INTEF )math") integrator
produces
t log(- 1)
%e Gamma(- t + 1,- log(x))
but this is messed up by later postprocessing. This is _very_ old
problem, but seem to show up with some frequency in integrals
involving Gamma (due to inconvenient choice of branches in
standard definition).
--
Waldek Hebisch
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