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1 = 0.9999999...


Sarka

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Dabookerman is wrong; it's not rounded, it simply is 1.

 

With each 9 added, it gets closer to 1. You have to stop writing it out somewhere, as it is recurring and you would run out of space. At the point where you stop writing, it isn't equal to 1, but taken as a whole, the number is.

 

Running out of space? Stop writing somewhere?

 

Kind of contradicts the 'recurring' bit. :woops:

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If 0.999rec = 1, then 9.999rec must = 10.

 

So if you multiply 0.999rec by 10, you are actually multiplying it by 9.999rec again.

 

If you put that in a calculator, it comes up with 9.9999989.

 

That itself should disprove the theory that 0.999rec is 1.

You can't use a calculator because it will round off the answer.

 

The reason you can't find anything wrong with those proofs is because they are right :heh:.

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How many 9's are there after the decimal point? If there's a set amount, then all of his equations are wrong. For example:

 

Let X = 0.999

 

•

Then 10X = 9.99

 

Subtract X from each side to give us:

•

9X = 9.99 - X

 

but we know that X is 0.999, so:

•

9X = 9.99 - 0.999

or: •

9X = 8.991

 

Divide both sides by 9:

•

X = 0.999

 

 

However, the ... after every number suggests that the 9's go on into infinity. Then we get the problem of infinity. The problem is, you cannot enter an infinate number into an equation and get an exact answer, you can only make an estimate. Take pi for example. This is used to find the area of a circle. To use the full number, you wouldn't get the calculation done, because the decimal places go on for infinity. Scientist have tried to see how far they can go before it finally ends, unfortuneately it's a random pattern, so goes on forever. They've mangaed to get it to several million decimal places, and it just keeps going. So to make things easier we round the number up to 3.14. This way, a calculation can be done easily. However, you will never get the exact number you require. But to get it perfect does not concern us, as it's a waste of our time. To round something up or down, simplifies it to the point we need. The only people who need to be precise in these cases are people like NASA. They needed to get the calculations for the mirror in the Hubble space telescope accurate to millionths of a milimetre in order for it to work. We only need to calculate as far as we can see. So to get it more accurate than say several hundred atoms either way would be wasteful, as there's not much an atoms difference is going to make in comparrison to what our own eyes see. OK this my be confusing, but basically, you only need as many decimal points as necessary to your bounderies. If you're measuring the area of a circlular section of say a clock face, you aren't going to be more accurate than a milimetre at most, because it isn't necessary. So we come back to the statement of 1 = 0.99999999... No this is incorrect! 0.99999999... going on into infinity never ever reaches the exact value of 1. It get's extremely close however. So close, that it isn't any cause of our own concern. Therefore at this stage, you can round it up to the nearest whole number "1" and say that's it's 1. In actual fact it isn't, but you can say it's pretty damb close. It's so close in terms of human thinking, that it really doesn't matter. We don't need to know how many billions of 9's there are after the decimal point as that's close enough to 1 for us to just call it 1 for simplicity. It's still not 1, but it's really damb close. The connection cannot be proven with an equation, simple as that. X will always equal the same number. Otherwise, it isn't an equation. Equations are all about equality. if this guy put that crap down in an exam, he'd get a big fat 0 marks, because an equation must be equal on both sides, so the value of X cannot change. That is impossible! This guy is only 14, he's only been doing algebra for about year or two, so his knowledge is limited.

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Good point Hal_9 million

 

I think we might need a maths graduate or something to give a definitive answer. I've just finished my a2, i know that his proof is not wrong in terms of the algebra. but i'm sure its wrong due to assumptions made about the recurring numbers and how to manipulate an infinite decimal place number, which is impossible surely.

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Plus this guy is only 14, just laugh at his infantile stupidity. Unless you yourself are also 14, or younger. Well I'm sorry if he's confused you. Tell him to talk to me, as I've just done an A-Level in Maths, so I could out-talk his misunderstood statements easyly.

 

 

And you'd think that elitism would be gone with post counts....

 

-edit-

 

Your post was perfectly fine until you started ragging on a guy that just asked a question. :hmm:

 

You obviously didn't A-level your elitist ass through English, did you?

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Plus this guy is only 14, just laugh at his infantile stupidity. Unless you yourself are also 14, or younger. Well I'm sorry if he's confused you. Tell him to talk to me, as I've just done an A-Level in Maths, so I could out-talk his misunderstood statements easyly.

Oh man, that post was hilariously funnny. Suffice it to say that you are indeed wrong. You haven't yet said why those proofs are wrong either. As I said, there is a reason for that...

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Well I did just write a long post pointing out the flaws in his argument, but IE crashed on me.

 

After changing to firefox...

 

My basic point was that the body of his post was both irrelevant and incorrect, and if 0.999rec wasn't equal to 1, then calculators and computers wouldn't work properly.

 

There was also no need for him to be so bilious.

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And you'd think that elitism would be gone with post counts....

 

-edit-

 

Your post was perfectly fine until you started ragging on a guy that just asked a question. :hmm:

 

You obviously didn't A-level your elitist ass through English, did you?

 

 

Oh, I'm sorry that it didn't make any sense for you written in my pigeon English. I just wrote a crap load of stuff in a short space of time, I don't give a shit about how good the English is. No I didn't study English A-Level, I wasn't interested, simple as that. That doesn't make me illiterate when I need to write something properly, but literacy isn't a top priority on these boards is it? OK, so having a go at someone for being younger isn't fair, but it's so fucking obvious that someone at that age isn't going to have a complex knowledge of maths. That's year 9 for God's sake, they've only been doing algebra for about year. Plus I simply hate smart arsed little shits!

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As far as I can understand it it goes like this.

0.999... Is a number which never ends. People who say "0.999... is always a little bit less than one" are wrong because the number in fact never actually ends and they are just assuming it to finish somewhere down the line.

The number is the same as the number 1 because the nines go off in to infinity.

 

That's the explanation as I understand it that the mathematicians give. I guess it makes sense if you think about it.

 

EDIT: It'd be the same for any number really that had recurring nines at the end.

 

Eg: 7.99... = 8

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Maths is all about impossibilities and theoretical assumptions; most of which are used in equations and advanced maths.

 

Mechanics is a section which often falls into this ideology. When calculating the speed of an object on a surface, you are often required to class the surface as perfectly smooth, where by the friction=0. This is impossible in our world, as no such thing exists, but we still use it in maths.

 

The same can be said about the 0.9999999999999rec=1 idea. It is all based around the degree of accuracy the people are looking for, but theoretically, it does equal 1. The further you go to infinity, the smaller the difference becomes, and it gets to a point where the gap is so minute that there is no point in classing it as a different number.

 

However, if you are classing 1 as purely one, ie a whole point, then yes, 0.999....does not equal one, However, maths dictates that it does, due to the theoretical, and often philosophical assumptions.

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As far as I can understand it it goes like this.

0.999... Is a number which never ends. People who say "0.999... is always a little bit less than one" are wrong because the number in fact never actually ends and they are just assuming it to finish somewhere down the line.

The number is the same as the number 1 because the nines go off in to infinity.

 

That's the explanation as I understand it that the mathematicians give. I guess it makes sense if you think about it.

 

EDIT: It'd be the same for any number really that had recurring nines at the end.

 

Eg: 7.99... = 8

 

 

no, no and no!

 

Look, if you draw a graph then 0.99999 recurring is an asymptote to the x=1 (whatever). It gets ever closer to 1 but Never, ever, ever will it equal 1.

 

So, this 0.99999 recurring = 1 stuff is just not true.

 

The problem is that the number X in the said equation is infitesimily smaller than 1. Rather than a quantifiable number.

 

Its something to do with the way maths works but i think the proof only works due to assumptions about infinite.

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Oh, I'm sorry that it didn't make any sense for you written in my pigeon English.

 

Actually it's pidgin, if I recall correctly ;)

 

Glad you edited your initial post though. And I really can't see him being 'smart assed' anywhere, but I won't deny I was :woops:

 

Hal_9million owns you all :)

 

Where the hell did that come from?

 

but it's so fucking obvious that someone at that age isn't going to have a complex knowledge of maths.

 

Hence why he asked the question? :hmm:

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