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 >