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Originally posted by: ZeroNine8
In your 'proof' you claim that for ANY N>0, .99...+.1^N>1 and claim that this is a strict inequality. However, since you are allowed to pick .99... then I'm allowed to pick N=infinity. In this case, you claim that 1>1 therefore, your assertion that the strict inequality holds for any N>0 fails, does it not? After this point, being able to nest .99... between 1+.1^N and 1-.1^N also fails, doesn't it? By my reasoning this allows 1-.1^N<=.99..., thus you have not constrained it to 1, only .99... or 1.
If this is not the case, what is the explanation for when N=infinity?
Consequently, by restricting N to real numbers (not infinity), you also kind of have to restrict .99... to some finite amount of digits at which point it's easy to prove .99... != 1
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N is restricted to the set of counting numbers, it must be specfied, specify a vaild N, infinity is not a counting number. The heart of the matter is that it is true for ANY specified N. This is what it makes it work and is one of the key concepts of the proof.
It ties into the fact that you must be able to specify the postion of every digit in a real number. This is another reason that the concept of an infinte number of zeros followed by a 1 is not a vaild number. You must be able to specify the value of the digit in the Nth position. For .999.... it is is easy if d(n) is the digit in the nth postion of the number I have d(n)=9 for all n. This is a basic part of the definintion of real numbers as an infinite geometric series. For the NON number .000...(infinity)1, you cannot find a d(n)=1 because you have already said d(n)=0 for all n. That is what is meant by an infinite number of something.