Date: Sep 30, 2013 4:09 PM
Author: LudovicoVan
Subject: Re: Is (t^2-9)/(t-3) defined at t=3?
"Julio Di Egidio" <julio@diegidio.name> wrote in message

news:l2ckfj$m9s$1@dont-email.me...

> "Virgil" <virgil@ligriv.com> wrote in message

> news:virgil-523099.13365230092013@BIGNEWS.USENETMONSTER.COM...

>> In article <l2bb8m$3gt$1@dont-email.me>,

>> Robin Chapman <R.J.Chapman@ex.ac.uk> wrote:

>>> On 30/09/2013 07:58, Ciekaw wrote:

>>> > On Saturday, September 28, 2013 6:30:42 PM UTC+2, Hetware wrote:

>>> > >

>>> >> But F(t) is not defined at t=3 because it evaluates to 0/0.

>>> >

>>> > Hint L'HÃ´pital's rule

>>> >

>>> > f(t)=t-3

>>> > f'(t)=1

>>> >

>>> > lim[f(t)/f(t)]=lim[f'(t)/f'(t)]=lim[1/1]=1

>>> >

>>> > Analogy:

>>> > If x=0 then sin(x)/x = 1

>>>

>>> Hetware: 0/0 = 3

>>>

>>> Ciekaw: 0/0 = 1

>>>

>>> Any more entrants?

>>

>> How about 0/0 = NAN ?

>

> 0/0 = |R, i.e. the entire real line, in closed interval arithmetic.

That is incorrect: 0/0 = |R*, i.e. the entire *extended* real line, in

closed interval arithmetic. I think it could be the negative or positive

half of it if one considers signed zeros, but I barely remember the details

right now.

Julio