Error in integrate

[Laurent Decreusefond]

Dear all, 

here is my problem

sage: var('t')

t

sage: integrate(e^(-2*t)/sqrt(1-e^(-2*t)),t,0,infinity)

-1

... a negative value for the integral of a positive function.

On the other hand

sage: integrate(e^(-2*t)*exp(-0.5*log(1-e^(-2*t))),t,0,infinity)

1

This is sage 4.8 on Mac OS.

[Michael Orlitzky]

On 04/14/2012 12:04 PM, Laurent Decreusefond wrote:
> Dear all,
>
> here is my problem
>
> sage: var('t')
> t
> sage: integrate(e^(-2*t)/sqrt(1-e^(-2*t)),t,0,infinity)
> -1
>
> ... a negative value for the integral of a positive function.

This is a bug in upstream Maxima. I've opened a sage ticket here,

http://trac.sagemath.org/sage_trac/ticket/12842

and reported it on Maxima's bug tracker here,

https://sourceforge.net/tracker/?func=detail&aid=3517785&
group_id=4933&atid=104933

[achrzesz]

Note, that
sage: integrate(e^(-2*t)/sqrt(1-e^(-2*t)),t,0,infinity,algorithm='sympy')
1

Andrzej Chrzeszczyk