Originally posted by: SilentRunning
Originally posted by: RossGr
Could you post refernces for you convention quote, I think it needs to be put in context. Though I do not disagree with it and I do not see that it mandates that 1 <> .999...
It specifies which representation shoud be used, not that multible representations do not exist. In fact, since it goes to some length to specify WHICH representation is to be used it is confirming that multiple repersentations EXIST. If there were not multiple repersentations of the same point on the number line such a convention would not be necessary. You would simply use the unique representation for the point you are talking about. But the fact is, multiple representations exist so an author is free to establish such a convention.
Generally an author can establish such a convention for HIS BOOK it does not mean that it is universally used. Axioms and Theorems are universal, conventions are local and may be different in different books or courses.
Yes multiple representations exist. You can represent 1 as 1.000... and 0.9999... but given 0.9999... as you have said as a just existing number does mean it equals 1.
As I have said you can intentionally divide 1 by itself in such a way that you get the end result 0.9999... but this ignores that there is a remainder. It would not be a number which "just exists" it only exists because of intentional manipulation.
Lets say that someone was to divide one by itself.
1 / 1 = 0.9999999999...
this would go on for hundreds of years, generation after generation. The multiply by 9 and carry the remainder. After several generations of math scholars one finally figures out that 1 can go into 10 ten times not nine. It takes several hundred more years to carry that 10 through all the 9's the previous generations had created. But finally they arrive at the answer 1.000...
You see 1/1 = 0.99999... is not non terminating by definition it is non terminating by choice.
Whereas given the non terminating decimal 0.9999... as a value as you have said it just exists.
There was no remainder invovled with its creation.