Re: Possible bug concerning a limit computation
- To: mathgroup at smc.vnet.net
- Subject: [mg71179] Re: [mg71107] Possible bug concerning a limit computation
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Thu, 9 Nov 2006 03:41:33 -0500 (EST)
- Reply-to: hanlonr at cox.net
$Version
5.2 for Mac OS X (June 20, 2005)
expr=(Sqrt[7x^4+6x+5]-Sqrt[7x^4+3x+3])*
Sqrt[63x^2-5x+20];
Limit[expr,x->Infinity]
9/2
Series[expr,{x,Infinity,0}]//Normal
9/2
Bob Hanlon
---- geo_topos <geo_topos at yahoo.co.uk> wrote:
> Hello everyone,
> I don't know if this is the right place to post this, but here it goes.
> I am a high-school math teacher from greece. I was working with my
> students on the limit:
>
> Limit[ (Sqrt[7x^4+6x+5] - Sqrt[7x^4+3x+3]) * Sqrt[63x^2-5x+20, x->
> Infinity]
>
> The result we got for that is 9/2. Mathematica 4.0 will produce the
> opposite result: -9/2.
> If anyone is interested on the way we calculated this limit, please
> e-mail me and I will be more than happy to send you a copy of our
> computation, since it would take me ages to type this in ASCII and
> furthermore it would be, at least, annoying to the viewer.
>
> Excuse my rusty english, best regards
> Kostas Raptis
>