Instigator / Pro
Points: 2

0.999... is NOT equal to 1


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After 5 votes the winner is ...
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Contender / Con
Points: 5
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Round 1
On my previous debate:
I definitely proved that 0.999 does = 1. The most compelling proof of that was:

X = 0.999...
10x = 9.999...
10x - x = 9.999... - 0.999...
9x = 9
X = 9/9 = 1

To prove that the conclusion is in fact wrong, i will repeat the same arithmetic on another number: ...999.0.

X = ...999.0
10x = ...9990.0
X - 10x = ...999.0 - ...9990.0
-9x = 9
X = 9/-9 = -1

Clearly something went wrong because even a single 9 before the decimal point is greater then 0, forget about an infinity of 9s. A negative number is an absurd conclusion, thus the argument that they are equal is reduced to absurdity.
This is interesting.
First of all, I want to thank you because you proved 0.999... = 1 for me. So there is no need to give some proof other than this.
But, in second "proof" you made mistake even before you started calculation. You said you will use same arithmetic on number ...999.0. And that is the mistake: number like this does not exist. Because if you said that number is ...999 then it is infinite number-there are infinite period of 9s after 0. and you can't just put 0 after infinite period of 9s otherwise it wouldn't be infinite... It isn't even a number. It's same as you wrote 0.999...0 - number like that does not exist.
Hope this proves my point.

Round 2
Your welcome, it wasn't something I was trying to hide.

However, it is contradictory to say that an infinite amount of 9s before the decimal is not valid, while accepting a number with infinite 9s after the decimal.
if ...999.0 does not exit, then neither does 0.999..., which invalidates the original proof of 0.999... = 1. Thank you very much. Please vote PRO! :)
It is contradictory to say that neither of our proofs are true and because of that one side or other should win. You tried to go off topic.
So, to review this shortly and clearly:
1) 0.999... IS periodic infinite number(check it anywhere, ask teacher in elementary school, if you aren't ashamed)
2) 0.999...0 (what you tried to calculate) IS NOT an infinite number like we said, because it has end-that's 0.

Don't vote for con, but VOTE for common sense. ;)
Thank you.

Round 3
2 correction:

1. Ending in zero doesnt make it any less equal to infinity. It has infinite 9s in front of it.

2. I was not trying to prove that ...999.0 = -1. I was trying to prove, as per topic, that 0.999... does NOT =1. Specifically by invalidating the method used to prove that it does and settle a long fought debate in mathematics.
1) You said, I quote: "Ending in zero doesnt make it any less equal to infinity." I am pretty sure that everyone reading this debate at the moment will agree with me that, if something has ENDING, then it is NOT INFINITE.
2) Objection to your second statement: You were trying to prove that 0.999... is not 1 BY proving that ...999.0 is =-1. So, if your method isnt valid and clear, conclusion from it cannot be any more valid or clear. :) 
Round 4
1. In numbers,  "ends in" refers to the smallest part of a number, the singles spot. Thus 1,000,009 "ends in" a 9. So having a zero in the last and smallest position doesnt change the infinite 9s before it. Hundreds, millions, billions, and on to infinity.

I trully do not understand the confusion here. Your argument revolving around "ends in" is essentially a play on words.

2. My opening statement, where i did the initial =-1 equation concluded with a declaration that both results are absurd. My arguments involved how similar the numbers and methods are, and I highlighted how if either one is invalid, both must be invalid.

Ill let #2 also be my closing statement.
As a bonus, i will show method to this madness with one more number:

X = ...999.999... 
10x = ...999.999...
10x - x = ...999.999... - ...999.999...
9x = 0
X = 0

Which again seems absurd... until you realize that 
...999.0 = -1
0.999... = 1
...999.999... = ...999.0 + 0.999...
...999.999... = -1 + 1 = 0

At least the insane equations work together :)
You found the truth my friend, we all live in matrix and all world around you is a simulation. Maybe this could be a topic for some other debate...
Seriously now, I wanted to give myself some logical answer to this "problem" and I did some research. And even basic math with infinity is just...well,undefined. So, for example:
infinity+ 1= infinity, but subtracting infinity from infinity, well we could call it 'not-a-number-ness', because subtracting from infinity doesnt have a definite result,so your calculations fall short because of this. You tried to subtract infinity, and I respect that try, minds like you could change a world for better, just focus on something more practical. :))
After all, many big mathematician brains have been thinking about this long before us, so if it is consensus, it is consensus because of these things I mentioned above,and many others for sure.
We really live in a world full of absurds and anomalies, but thank you for high-quality debate.
Hope to see you in some next debates.
P.S. This could be named a 'tie' but let the votes prevail. :)

--> @Nemiroff
I'll show you the infinite geometric series proof that I forgot to explain in full last time.
Before I go on to proving that 0.999...=1, I need to establish what an infinite geometric series is. Before I can do that, we need to establish what a geometric series is. Before that, I need to define what a series is.
A series is simply the sum of a sequence. A sequence is just a set of numbers. For example, 15 is the sum of the series [1,2,3,4,5] (the square brackets are just the formal way of showing a set). If you add all the numbers of the sequence together, you will get 15.
A geometric series is a series in which each subsequent number in the series' sequence is multiplied by some constant. There will be the first number in the sequence, and then that number will be multiplied by something to get the next number, which will be multiplied again by that something to get the next, and so on and so forth. Let's define the first number as "A" and the constant which "A" is being multiplied by as "R". These variables are completely arbitrary, and we can call them whatever we want. Given these two variables, we can now define our geometric sequence in a mathematical sense.
The first number of the sequence is just A, by definition.
The second is A*R, since a geometric sequence is, by definition, in which each subsequent number in it is the previous one multiplied by a constant. This can be rewritten as AR.
The third is AR*R, since we are multiplying the last term by the same constant (R). Since R*R can be rewritten as R^2, this term can be rewritten as AR^2. One important thing to remember is that the exponent of something simply denotes how many times that variable is multiplied by.
The fourth term is AR^3, since the previous term is AR^2 and we are multiplying it by R again.
[continued in next comment]
--> @oromagi
Subtraction is a valid operation.
I did 10x - x = 10x -x in the proper order
10x is the ...9990.0
X is ....999.0
10x - x was equal to ...9990.0 (aka 10x) - ...999.0 (aka x)
It was all in the proper order.
Does that negate your entire vote? And how do i bring this comment to the proper mods attention if it does?
--> @RationalMadman
So... let me get this straight:
10-0.999...=0.000...1, correct? Ok.
The "..." in 0.000...1 represents an infinite number of 0s before the one. Since there is an infinite number of zeros, there will always be a 0 after the previous one. Thus, the 1 at the end will never be reached. Since the 1 will never be reached, 0.000...1 is the same as 0.000..., which is simply 0.
Going back to our equation, we now have 10-0.999...=0
Adding 0.999... on both sides, we get 10 = 0.999...
--> @RationalMadman
Im unsure of that conclusion, but i am sure about your error. So i will be arguing a bit of devils advocate based of my previous mindset.
If one were to try to manually calculate all the 9s... even given infinite time no they will never reach that final 9 that makes it a one...
But the number itself is not growing 1 number at a time. It is in its entirety now. All infinite 9s are there inside of its definition. And *at the point of infinity*, when all infinity of that number is valued at once. It is equal to 1.
Its like an asymptotes in math class. It approaches the line, but never reaches the line as far as you can see... but if you extend that line to infinity, it does meet the line at that infinite point.
--> @Nemiroff
Then you will admit that 0.999... never becomes 1.000... because it forever can never reach it.
--> @RationalMadman
Red pill time.
The issue isnt whether its a 9, a 1, or a 0. The issue is with the concept of "last". There is no "last". When faced with an infinity, last has no meaning.
There is no last. There is no after. Thats the reality of infinity. Your sentences dont make any sense in the context of infinity.
The only way to negate this concept is to show how mathematically absurd it is with similar examples, as i tried.
--> @Nemiroff
Do you think because the last 9 of 0.999...9 happens to be the same digit as the others means it's more attainable than the '1' at the end of 0.000...1?
--> @RationalMadman
I dont understand what your referingto with the "just as" in that first sentence, but i think the key is in my last question.
Can there be a last, or an after, in an infinite series?
--> @Nemiroff
Just as much as the infinite 0's followed by a 1 that is the difference has the '1'.
So, I'd totally concede the '1' is never reached, and neither is the '9' because recurring numbers basically can't truly exist in their base. Base-10 doesn't allow for 1/3, it also doesn't allow for whatever sum you use to get 0.999... to ever be equal to 1 unless you abusively play around with algebra in a one-way-conversion pseudo trick that revolves around the fact that 0.9999.... is a fake value.
Does a series of infinite 9s have a "last" 9?
Then it never reaches the last 9.
--> @RationalMadman
There is no after the infinity. The most you can say is "at the point of infinity". Before that point 0.999... "approaches" 1, but the number isnt actually changing with time or approaching anything. If you take the number as a whole, "at the point of infinity" it supposedly becomes 1.
Im not sure of that conclusion, but i am sure of your "after infinity" flaw. 0.999...x does not exist, there is no "x", it will always be "..." with no end. Whether the x is another 9 or a different number, there is no final digit. Ever. Your notation doesnt make sense.
--> @Nemiroff
So after the infinity it never adds on the 1 to become 1 from the 9, yes?
--> @RationalMadman
There is no "after" with infinity. There will be 9s, none of them are after the infinity. There will never be a 1, or any number not part of the repeating pattern.
The problem with your logic is your insistence on an "after the infinity". Thats a ludicrous statement by itself.
--> @Nemiroff
1 after infinite 0's is directly comparable to a 9 after infinite 9's. Just as unattainable.
Criterion Pro Tie Con Points
Winner 1 point
First of all, whatever either said elsewhere, is not proof within this debate. Second, there's no need to accuse anyone of living in the matrix.
While I did not find pro's math convincing, it was more than I did not find his math convincing as opposed to finding con's counter case convincing (maybe breaking R1 into multiple paragraphs would have helped; and yes, for confusing stuff like this, it's really best to break the concepts apart).
I will say that infinite 9's to the left of the decimal, probably wouldn't change to infinite 9's followed by a 0 when multiplied within the base-10 system.
Criterion Pro Tie Con Points
Winner 1 point
This Math is really confusing my brain, and I feel like oromagi and Madman have covered the Math part really well, way better than I could have every tried. But here's my opinion on the non-Math things...
Neither of you guys had a format, or a full speech, even though you were given 5000 characters to do so. With a 5000 character limit, I would except solid arguments with a clear format and organized clash, but that wasn't present here.
Pro however contradicts himself using himself in the first round, which I find quite odd. He tries to disprove his own case, but ends up cancelling his case out. Con takes notice of this.
Due to that reason, and the other voters reasons, Con wins.
Criterion Pro Tie Con Points
Winner 1 point
PRO begins with solid evidence for the notion he has offered to disprove and then promises to disprove the notion using the same equation.
But PRO uses a new equation (10X - X =/= X - 10X), inserting a negative result and proving zilcho. Likewise, he replaces the irrational value of his equation with an infinite number which behaves quite differently.
Either side arguing for the "existence" of one irrational or infinite number is oxymoronic when by definition such numbers can't be accurately represented much less exist. e. I don't think PRO is using correct or legit notation for infinite nines but when CON tries to de- legitimize an infinite number of nines multiplied by arguing the irrational number he is not persuasive.
Ultimately, PRO loses this argument because he promises a magic reversal but we can see the chosen card peeking out of his sleeve.
Criterion Pro Tie Con Points
Winner 1 point
Pro did two things wrong in this debate, despite being on the objectively correct side. I don't know how he even made these errors as I have personally outside of this debate provided him the killer proofs that 0.999... is not equal to 1.
The first thing he did wrong was to bother using the erroneous algebra construct that people use to hocus pocus 0.999... to be equal to 1, then to replace it with 999.0 (instead of 999.999... which would indeed end up making it equal to 1000.000 and that's the whole point, that algebra construct enables erroneous conversion). This was correctly attacked by Con, albeit with strange wording, in the following Round. Con of course is erroneous because the attack Con uses is that 0 can't follow infinite 9's. What Con should have argued was that the number at the start was not at all like 0.999... since it doesn't have infinite 9's following the decimal point.
Pro does start to tackle this in the way I have introduced Pro to outside of this debate but Pro does it wrong. Instead of pointing out that if 0 can't follow infinite 9's, neither can the imaginary '9' at the end of it all, Pro decides to play around even more with the abusive algebra which Pro should be showing is corrupt because you can't reverse engineer it (the fact you can never start with 1 and end up with 0.999... means that there is clearly something erroneous about the algebra, even if you completely flip around the equations, you never end up with 0.999... at the start, this key way of negating the algebra isn't employed by Pro in the entire debate). Pro starts to keep almost joking around with his 'proof' that 0.999... is not equal to 1 with some really confusing algebraic display that tries to show you can make something else happen with algebra and infinite series that involve 9. This had nothing to do with the debate. What Con does is also very silly and minimalistic, but I know why Con did that. Con is on the side that is a lie, therefore Con's best bet at winning is to avoid going into details and depth and instead sticking to rhetoric like "a 0 can't follow infinite 9's therefore you are wrong" well, neither can a 9... But Pro doesn't hit that point home.
Neither side brought up the 1/3 - 0.333... angle, this is a much stronger case for Con to make as it's backed up by school syllabus content (which lies but is considered highly reliable due to what it is). This then means that 1/3 * 3 technically equals 0.999... and the only way for Pro to counter it is to expose that 1/3 does not equal 0.333... but instead equals 0.333...0333...0333 infinitely over and over again. Pro doesn't do this but Con doesn't bring it up.
Since this debate is structured with Pro having the burden of proof and since Con does kind of 'hit home' a point about that 0 can't follow infinite 9's and pro doesn't turn it back on Con with the '9' following the infinite 9's, Con takes the win.
Criterion Pro Tie Con Points
Winner 1 point
Pro opened with two mathematical equations that contradict each other. Con denied that the second equation was valid because he claimed ...9990 doesn't exist. Con then attempted a play on words to say that 0.999...0 doesn't exist because an infinite number can't end. Pro refuted these claims by pointing out that the existence of 0s at the beginning or end of a number does not prevent there from being an infinite number of 9s before the end or after the beginning.
Overall, neither side was able to prove their case. Pro relied on contradictory equations and Con stuck to attempts to refute Pro's claims.
The only source was Pro citing himself. Both sides had good conduct and S&G.