Bug in limit or integrate



 ----"Richard Hennessy" <rich.hennessy at verizon.net> wrote: -----

>I should not have used the abs() function. This is a simpler answer and it 
>does not blow up at zero.

>(gamma(1/4)/4-gamma_incomplete(1/4,x^4)/4)*signum(x);

OK, this antiderivative is valid on the reals. An antiderivative that is valid on the entire complex plane
is x |-> x*hypergeometric([1/4],[5/4],-x^4). But Maxima is unable to compute limits of hypergeometric
functions, you are out of luck if you used this antiderivative to try to compute integrate(exp(-x^4),x,minf,inf).

Some definite integrals of exp(-x^4) are broken:

 (%i6) integrate(exp(-t^4),t,0,1);
 (%o6) (%i*(gamma(1/4)-gamma_incomplete(1/4,1)))/4

--bw