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Old 10-24-2008   #55 (permalink)
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Re: A Mathematical Emergency.

Quote:
Originally Posted by Don Blazys View Post
...there are plenty of cases, contexts and circumstances in which equations such as:
(0/0)=1 can be viewed as "meaningfull". (Especially in the context of "limits".)
Gosh Don, I was talking about the blunt \frac00 form and I said so. I was distinguishing it from limits of any kind of expressions in the exponent.

In terms of limits, it is clear that the ratio of two infinitesimals (a distinct thing from the ratio of 0 and 0), can have a limit of any value (according to what the two infinitesimals are). It is also trivial to argue that any limit of:

1^{f(x)}

exists and can only be equal to 1. By "any limit of" I mean the limit for x approaching any accumulation point of the domain of f.

\frac00 has no domain, no accumulation points, it cannot have any limit. It simply does not and cannot define any value (for any value of x or any other variable).

Do you understand the distinction Don?

Quote:
Originally Posted by Don Blazys View Post
There are, however, no conditions under which equations such as:
(6/0)= N can be construed as meaningfull, so the expressions:
Obviously, if by N you mean a finite value! (or an infinitesimal one) You attempted a sleight of hand here!

Quote:
Originally Posted by Don Blazys View Post
Also, (0/0)= (infinity) if and only if (infinity)*0=0. (Again, the meaning/value of (0/0) depends entirely on the context in which it occured.)
This gets you into the same paralogism I had already pointed out.

Quote:
Originally Posted by Don Blazys View Post
I suppose that different mathematicians have different criteria for what constitutes a "valid result". For me (and most mathematicians my age), those criteria are "consistency" and "beauty".
This is a very dubious statement, self-consistence is a criterion of validity, but beauty is not.


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Last edited by Qfwfq; 10-24-2008 at 08:38 AM..
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