How does one (i.e. automatically in an own program) recognize existence of a limit?
So far I've discovered that -oo, oo, ind, und cause the non-existence, I just dunno how to test these "values". Obvious
if limit(f, x=oo, dir='+') == und:
...
does not work...
Sage 5.1 Kubuntu 12.04
Hi as far as I understand the problem is that oo so on are symbolic expressios. If you try to compare them with == sage returns as a new symbolic expression the symbolic equationion:
var('x,y')
print x==y
print type(x==y)
returns
x == y
<type 'sage.symbolic.expression.Expression'>
A soultion seems to be to cast the symbolic equation to a boolean:
print bool(x==y)
print bool(x==x)
which returns
False
True
Hmm, that's true. We allow it as a result from Maxima for e.g. lim(sin(1/x),x=0) or your example, but I guess we just print it out. I've made this http://trac.sagemath.org/sage_trac/ticket/13269, though I'm not sure what exactly could be done.
Asked: 2012-07-18 07:04:23 +0200
Seen: 953 times
Last updated: Jul 18 '12
Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.
