Poll: 0.999... = 1

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USSR

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Don't start this again. <.<

I thought it quieted down..
 

Jaime_Wolf

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Jul 17, 2009
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Coldie said:
Lyx said:
@Jaime

I disagree. .999... is a process, not a number. I have never seen anything else, and i cannot even MEAN anything else... this is not just a matter of "imagination".... the value which you claim infinity is, is not constructable in our minds. It also isn't constructable in a machine. In fact, it NOWHERE is constructable.

It does not exist. All that exists is a looped process.
It exists in math. N-dimensional lattices exist in math, but you can't construct one in your mind. Just because something may be incomprehensible, does not mean it doesn't exist. 0.(9) is a number. Some of its representations are infinite. There are no processes there, they just are.

Math is axiomatic and absolute. If a system or a theory says something works in a certain way, then it just does, within that system. There is no intuition, there is nothing to comprehend, there is only Math and its laws, as defined by the System's Postulates. If you deny an axiom and substitute your own, you create a new system with a new ruleset. If you do it as a part of a proof, the proof is invalid in the original system and therefore irrelevant.

Sufficiently advanced math is indistinguishable from magic.
I didn't say that all of math was intuitive, I said that all of mathematics finds its base in intuition. Axioms, by definition, exist either to codify intuitions (intuitions that we find basic and inescapable) or to solve paradoxes that arise when those intuitions collide. The sort of austerity you describe is an illusion created by the latter type of axiom: the sort that are required to maintain consistency within the system described. The problem is that when we take our basic intuitions and attempt to form more complex naive theories by extrapolating from them without extreme care, we introduce errors into our computation. Mathematics is, in essence, a way to perform careful extrapolation from our basic intuitions. It's ludicrous to claim any alternative. If mathematics doesn't stem from intuitions, where does it come from? You end up some sort of bizarre Platonist. Intuitions are all you've got. If you're actually interested in these questions, you should look into the philosophical foundations of mathematics and philosophy of science in general. There's some good discussion in the developmental psychology literature regarding acquisition of number theory as well.

People who know mathematics do not necessarily know the underpinnings of mathematics and it's statements like this, talking about how mathematics is somehow disjoint from reality and intuition, that lead the general public to reject complex mathematical results.

RE the actual question: If you don't think .999...=1, you probably think that it's less than 1. If it's less than one, you need to add something to it to make it one. What are you going to add? .000... with a 1 and the end? If there are an infinity of zeroes, WHAT END?

The issue of infinity as a number not being useful in the real world is also blatantly false. Many of these issues are extraordinarily important in physics and engineering. See therodynamics, hydrodynamics, and electrical engineering in particular (specifically regarding complex analysis).
 

Lyx

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Sep 19, 2010
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ultimateownage said:
No it's not, but the difference between 0.9*[footnote]the * represents recurring.[/footnote] and 1 is 0.0*1 and since there are infinite 0's then the difference is infinitely small.
Anyone with a basic understanding of maths can tell the difference between equal to and infinitely close to.
Careful with the wording: "infinitely close to" can easily be adapted to allow equality. I agree with what you wanted to say however.
 

Boris Goodenough

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Jul 15, 2009
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This is a question of limits for asymtotes, and the function used to obtain these values is called lim.
So for this case is
lim(x)=1 for x -> 1

It's used in the proof of integrations and differentials. Where you slice the lines infinately thin and then add up.
 

Sovereignty

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Jan 25, 2010
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I think anything that tries to grasp at infinity is flawed. Even if just on the grounds that one can't possibly understand what it doesn't know.

No one knows what happens once you count to infinity. Because as living creatures we cannot. I assume the clouds open up, God rides a flaming unicorn to the front of your house/apartment, and proceeds to teach you how to actually beat The Sims.

PS: No your Sims dying without children doesn't constitute *beating* the game. Duh.
 

SpecklePattern

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May 5, 2010
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Rawle Lucas said:
havass said:
If x = 0.999999...
Then 10x = 9.9999...
Therefore, 10x - x = 9
Which implies 9x = 9
Thus, x = 1
x also = 0.99999...

In conclusion, I have just proven 1 = 0.9999...
The odd thing is that your proof is correct.
I really don't want to read all post and people might have said this, but

9.999... = 9 + x =/= 10x - x = 9x = 8.99999999...

But if you don't want to be exact, you can always say that 0.99999 is 1. But there is no equal sign in there. Two different numbers are not equal.

epninja said:
1/3 = .3333...

therefore 3/3 = .9999... = 1
And this is why we have different number sets like rational, irrational and real numbers :)
 

SenseOfTumour

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Jul 11, 2008
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Maybe I'm not being scientific enough but, isn't the answer that it's close enough that no-one should really care if it is or not?

If I had to choose between a million bucks and 0.99999... of a million bucks, I wouldn't waste a lot of time thinking about it. (it'd be the million because the other option might be a trap.)
 

Valkyrie101

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May 17, 2010
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Doesn't matter how much algebra you do, 0.999999999 of anything is less than a complete one. Therefore, they are not the same.
 

Coldie

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Oct 13, 2009
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Piflik said:
See...perfectly correct and logical...
There is no such thing as 'end of infinity'. Please try harder next time, lest the infinity stares back into you.
 

TraderJimmy

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Apr 17, 2010
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Klopy said:
Some of the math in this thread is flawed... jeez. Double check, please. :p

.9999... is not equal to 1.
Why?

Still being in high school, and with my chemistry background, I would have to say that .9 etc. is not equal to 1 because of its significant figures. You can round up when the math is over, but it will never be correct. .9999999 will always be <1, no matter how close it gets. In the math world, this is just how it has to be.

In real life, it would get so close to 1 that it wouldn't really matter.
But in theoretical conversations, it will always be <1.
Why is everyone seeming to argue that this infinity needs to be calculated in real time?

By which I mean, people are saying "Sure, you can keep adding those 9s, but you'll never actually reach forever."

It doesn't reach forever, true. It just is.

It is infinite, right now. It won't "never reach forever", it is forever already.

That's what infinite means.

I...I don't get what's difficult about that.

Still, not a Math Major here, maybe infinity is treated differently in maths. I'd find it difficult to calculate with an infinity that actually equalled an ever-fluctuating rational number though, myself.
 

Piflik

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Feb 25, 2010
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Coldie said:
Piflik said:
See...perfectly correct and logical...
There is no such thing as 'end of infinity'. Please try harder next time, lest the infinity stares back into you.
I know there is no end to infinity...that's why I called it theoretical 'end'

This whole argument is a theoretical one, since there is no such thing as infinity in reality ;)
 

Coldie

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Oct 13, 2009
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Piflik said:
I know there is no end to infinity...that's why I called it theoretical 'end'
There's no theoretical end to infinity, either. Infinity is infinite, it has no end. At all. It might have a beginning, but never an end. It might be countable or uncountable, but it never, ever ends. Ever.
There is never a zero, there are only 9s. When you shift the digits left, it's still just 9s going on forever. If there's ever a shortage of digits, you could just shift it left and mine the integer part for a nine, then repeat (forever!).

Math is so simple, yet so easily misunderstood.
 

Lyx

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Sep 19, 2010
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Jaime_Wolf said:
Then you disagree with the question, not the result (since the answer of an incoherent question cannot be true or false). Assuming you take the view that this is an erroneous question, you should probably realize that you are, in the end, arguing that all real numbers are only processes (Values having multiple representations stems from the nature of constructing representations of real numbers. So you can, for any real number, create a number system that forces you to conclude that the values are processes). As soon as you take such a view, you either have to abandon a notion of equality altogether or you have to say that they're equal. So nothing is really ever gained.

Och jaime. See, we (from my POV) don't even generally disagree with each other. I am very well aware, that i have been walking on very thin ice by making a distinction between numbers and processes (the connection is that "values" (i dont know the right word) can indeed be represented as direct numbers as well as processes, so that indeed a process and number can refer to the same value). We're on the same line about the background-theory.

What i disagree with - as hinted earlier - is purely the definition of the "term" infinity. See, i'm someone who defines a lot of things different than others. That is because i do not just accept terms simply because someone says so. I look at how the terms are used, how they are related to other terms, and so on - so, i have a tendency to define terms according to which meanings are actually communicated with them (instead of the claimed meaning). I'm aware that this approach has some pitfalls and issues, but while being aware about them, this approach has served me very well for many years.

In the case of infinity, i look at what happens in practice when it is used. And that is simply a repetition-process. That this is how most people understand this term, is all too visible precisely with the 0.999... question. When someone says "add 9's infinite times", then i take it to mean just that.

Sure, you can argue that how doing precisely this, makes little sense, if one considers the theoretical backgrounds - and that therefore, we should "correct" the result to what makes sense. I don't even disagree that "functions" like this should work different than "infinite times 9". But as mentioned earlier, if the instruction should be different, then use a different instruction, not the "wrong" one with the "right" meaning.

So, our disagreement ultimately is simply one of language, not one of concept.
 

brunothepig

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May 18, 2009
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smithy_2045 said:
brunothepig said:
havass said:
If x = 0.999999...
Then 10x = 9.9999...
Therefore, 10x - x = 9
Which implies 9x = 9
Thus, x = 1
x also = 0.99999...

In conclusion, I have just proven 1 = 0.9999...
No, no no no. The problem with that proof is the whole infinity thing. Infinity is just a concept. Basically, 10x0.999.. should equal 9.999..8
Because infinity is supposed to be, well, forever, the 8 is kinda ignored in that proof, but it should be on the end of that never ending number. You see why it's a problem?
OT: I think my stance on this is rather obvious. 0.9 recurring doesn't equal 1. It is in fact, 1x10^(-infinity) less.
Which is equivalent to zero. Which means there is no difference. Which means .999... = 1
It isn't equivalent to zero. That was my point, infinity is the concept of "as close as you can get without being it"... Kinda. 1x10^(-infinity) would equal 0.(an infinite number of zero's)1.
Basically, the difference between 0.9 recurring and 1 is infinitesimally, immeasurably small. But they are not equal.
 
Jun 11, 2008
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popa_qwerty said:
Glademaster said:
havass said:
If x = 0.999999...
Then 10x = 9.9999...
Therefore, 10x - x = 9
Which implies 9x = 9
Thus, x = 1
x also = 0.99999...

In conclusion, I have just proven 1 = 0.9999...
I hate this theorem worse than the making 2=1 through dividing by 0.

OT: Yes technically speaking in maths 0.9999... is equal to one. For more counterintelligence ideas. Since every atom is mostly empty space me, you, your family, the walls around you and everything you have ever known is mostly empty space. Thus everything ever is a waste of space:p.
and this world of empty space is nothing but what we conseve it to be;;ps

pardon my bad English[/quoteMeh
Meh it's fine. Only 1 word spelt wrong. Although it is funny how we never actually touch thigns either on an atomic level.
 

CrashBang

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Jun 15, 2009
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BlacklightVirus said:
havass said:
If x = 0.999999...
Then 10x = 9.9999...
Therefore, 10x - x = 9
Which implies 9x = 9
Thus, x = 1
x also = 0.99999...

In conclusion, I have just proven 1 = 0.9999...
I prefer:

b0.b1b2b3b4... = b0 + b1(1/10) + b2(1/10)^2 + b3(1/10)^3 + b4(1/10)^4 ...

if |r| < 1 then kr + kr^2 + kr^3 + ... = kr/(1-r)

So for 0.9...:

0.(9) = 9(1/10) + 9(1/10)^2 + 9(1/10)^3 + ... = (9(1/10))/(1-(1/10)) = 1
That's not maths! That's mystical, magical witchcraft! Burn the witch!
(Maths wasn't my strong point in high school)
 

Rainforce

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Apr 20, 2009
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yes, 0.99999 is 1, but only in the weak human interpretation of the concept of Mathematics.