Subject: limit(erf(z),z,infinity) (Was Re: limit of erfc)
From: Raymond Toy
Date: Fri, 18 May 2012 08:41:17 -0700
On Thu, May 17, 2012 at 8:53 AM, Raymond Toy <toy.raymond at gmail.com> wrote:
> I noticed when running just the rtest_gamma test, I get two failures:
> limit(erfc(z),z,inf) and limit(erfc(z),z,minf). This doesn't happen when I
> run the entire testsuite. I guess something is leaking into rtest_gamma
> from earlier tests.
>
> However, from a fresh maxima session, maxima cannot determine
> limit(erfc(z),z,inf). But maxima knows limit(erf(z),z,inf) = 1.
>
>
Here's something, uh, interesting:
limit(erf(z),z,infinity) ->
-%e^-infinity^2*(sqrt(%pi)*(2*infinity^7+infinity^5+4*infinity^3+6*infinity)
-3*%pi*%e^infinity^2*erf(infinity))
I'm not sure what to make of that. Shouldn't the answer be a plain und?
limit(tanh(z),z,infinity) seems to get into some kind of loop, or maybe I
didn't wait long enough, but shouldn't the answer there also be und?
Ray