Drexel dragonThe Math ForumDonate to the Math Forum



Search All of the Math Forum:

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.


Math Forum » Discussions » sci.math.* » sci.math.independent

Topic: Is (t^2-9)/(t-3) defined at t=3?
Replies: 166   Last Post: Oct 30, 2013 9:41 AM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Peter Percival

Posts: 1,218
Registered: 10/25/10
Re: Is (t^2-9)/(t-3) defined at t=3?
Posted: Oct 7, 2013 10:30 PM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

Hetware wrote:
> On 10/6/2013 11:51 PM, Arturo Magidin wrote:

>> repeating it, well, you can guess what that implies...
>>

>
> That you have little of value to contribute. The context was reasonable
> clear. If you wanted clarification, you should have asked for it.


Ho ho ho.

>>> In this case, the domain is all real numbers were f(t) is defined.
>>
>> That was the point. But you are trying to extend this from "where it
>> is defined" to "wherever I can define it irrespective of the formula
>> given".
>>
>> I say right after:
>>

>>>> Because this becomes both onerous and complicated, there is a
>>>
>>>> standard convention that is, I am positive, mentioned in your
>>>> book.

>>>
>>>> This convention is:
>>>
>>>>
>>>
>>>> If a function is described by giving a formula, and no domain is
>>>
>>>> explicitly specified, then it is agreed that the domain of the
>>>
>>>> function is the natural domain: that is, the domain is the set of
>>>> all

>>>
>>>> numbers for which the expression, *as given*, makes sense.
>
> Ah, but there's the rub. It did make sense to me to treat the function
> as defined where t=3.


It hardly makes sense to "treat" something as if it had a property that
it doesn't.

> Until I was able to sort out the axiomatic
> ordering of assumption, I was confused by applying an assumption that is
> generally applicable in the domain where I apply mathematics.
>

>>> and the observation that
>>>
>>> (t^2-9)/(t-3) is meaningful for all t!=3 dictates that f(3)=6.

>>
>> Nope. Because
>>
>> (i) "f(t) is continuous" does not mean the same thing as "f(t) is
>> continuous everywhere"; and

>
> At this point, I already stated that it is continuous for all real
> values t. You simply chose to ignore that fact.


f is not continuous at 3 because it isn't even defined there.

>> (ii) Because by asserting that f(t) is continuous you are ASSUMING
>> that f is defined at 3.

>
> You are finally catching on to what I was saying.
>
> However, whether or not f(t) is defined at 3

>> is *precisely* the crux of the matter here.
>
> I defined it as continuous.


You don't define a function as continuous. You define it and then
deduce that it is continuous if it is so.


--
The world will little note, nor long remember what we say here
Lincoln at Gettysburg


Date Subject Author
9/28/13
Read Is (t^2-9)/(t-3) defined at t=3?
Hetware
9/28/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Michael F. Stemper
9/28/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
scattered
9/28/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
9/28/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
9/28/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
9/28/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
9/28/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
9/28/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
9/28/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Richard Tobin
9/28/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
9/28/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
tommyrjensen@gmail.com
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/6/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/6/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/6/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/6/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
10/8/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
10/7/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Michael F. Stemper
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/6/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/6/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/7/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/7/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
LudovicoVan
10/7/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/8/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/12/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/12/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
fom
10/13/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/13/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Richard Tobin
10/13/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/13/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/13/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
fom
10/13/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/13/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/8/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
10/8/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/8/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
10/8/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
10/12/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/13/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
10/13/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/9/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/9/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
fom
10/10/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/10/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
fom
10/7/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/7/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/7/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
fom
10/7/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
9/30/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
9/30/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
9/30/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
9/30/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
RGVickson@shaw.ca
9/30/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Roland Franzius
9/30/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Richard Tobin
9/30/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
RGVickson@shaw.ca
9/28/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
9/28/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
9/28/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Virgil
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Virgil
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
LudovicoVan
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Virgil
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
FredJeffries@gmail.com
9/30/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
9/30/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/6/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/6/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/6/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/6/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/6/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/6/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/6/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
David Bernier
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
9/28/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
9/29/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Richard Tobin
9/30/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Ciekaw
9/30/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Robin Chapman
9/30/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Virgil
9/30/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
LudovicoVan
9/30/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
LudovicoVan
10/6/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/7/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Robin Chapman
10/7/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
David Bernier
10/7/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/7/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
LudovicoVan
10/8/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/9/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/9/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Richard Tobin
10/7/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/8/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/8/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Virgil
10/8/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/9/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/9/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/10/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Ciekaw
10/9/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/10/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Tim Golden BandTech.com
10/13/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/13/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/13/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/14/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/13/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/13/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
fom
10/13/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/13/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
fom
10/14/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
fom
10/14/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/14/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/14/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/14/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/14/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/14/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
10/16/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
@less@ndro
10/16/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
10/19/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/19/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
10/19/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/20/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
fom
10/20/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
10/20/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/20/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
fom
10/20/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/20/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/20/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Richard Tobin
10/20/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/30/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
@less@ndro
10/19/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/10/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Ronald Benedik
10/10/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/10/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Virgil
10/18/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/19/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/19/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
fom
10/19/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/19/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/19/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/19/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/19/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
fom
10/19/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/19/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/19/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/20/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/20/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
10/20/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
quasi
10/20/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/20/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Peter Percival
10/20/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/20/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/20/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Arturo Magidin
10/20/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
Hetware
10/20/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
magidin@math.berkeley.edu
10/19/13
Read Re: Is (t^2-9)/(t-3) defined at t=3?
fom

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2014. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.