Robert Marik <marik <at> mendelu.cz> writes:
>
> I cannot find the mistake, since I am not familiar with lisp and I
> cannot check the changevar command in sources, but this problem
> disappears if you do substitution x=1/cos(t) in the integral
> x/sqrt(1-x^2)
>
One more information: there are no problems with similar integrals
x/(x^2+4) and substitution x=tan(t)
x/(4-x^2) and substitution x=sin(t) - both work fine
the problem is only with x/(x^2-4) and x=2/cos(t)
Robert M.