On Wednesday 31 December 2008, Jaime Villate wrote:
> On Qua, 2008-12-31 at 13:53 +0100, Michel Gosse wrote:
> > With maxima 5.14 :
> >
> > limit((7-x)*exp(x-4),x,inf)
> > inf
> >
> > I think i must obtain minf ?
>
> You're right, and Maxima 5.16 is also right:
>
> Maxima 5.16post http://maxima.sourceforge.net
> Using Lisp SBCL 1.0.11.debian
> (%i1) limit((7-x)*exp(x-4),x,inf);
> (%o1) minf
>
> By the way, this example puzzles me because the function is clearly
> negative for x>7, so the limit must be minf, but it can also be written
> as:
> limit((7-x)/exp(4-x),x,inf)
> and applying L'Hopytal's rule:
> limit(1/exp(4-x),x,inf)
> which is inf. What's wrong with this?
>
You can't apply L'Hopytal's Rule:
diferent limits
limit((7-x),x,inf)=minf
limit(exp(4-x),x,inf)=+0
Right?
> Regards,
> Jaime
>
>
>
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--
N.Lopes
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