2010-03-13, 02:54 AM
Kabanaw Wrote:No matter how many figures you go to in any real life application, it will always round to 1. So for any practical purposes, .99999....=1.
It's not just for practical purposes. it IS equal.
Since the number line is ordered numbers can be compared. If a and b are two different real numbers, then there exists at least one real number between them (actually infinitely many of them). (a+b)/2 is the easy way to find such a number. Otherwise if the average of a and b is either a or b then a = b. Which is what occurs in the case: 1.99999.... divided by 2 gives you .999999999..... and it will never stop. Thus .999999....=1.
Or how about this, since there has to be another number in between two real numbers: Attempt to construct a real number bigger than .999..... but smaller than 1. It's impossible. Thus .99999......=1.

