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# .9 Repeating = 1 YES -or- NO

## Does .9 Repeating equal to 1?   116 members have voted

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Samoa    0
OMG, this can't be done on a freaking calcluator because it goes on to infinity you idiot!

0.9 recurring is a rational number, the same way that 0.3 recurring = 1/3. FOOL

please refrain from calling others fool or idiot. :rolleyes:

Face it your calculations were wrong.

also for those who suggest you need to subtract from both sides...

x=.9999

10x-x=9x-x will never work out cause you don't have equality. 9 and 10 are not the same.

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Samoa    0
x = 0.9999...

10x = 9.9999...

10x - x = 9x

9.9999... - 0.9999... = 9

9 = 9x

1 = x = 0.9999...

I think you a made a mistake:

10x = 9.9999

but why subtract x then? that doesn't make sense. You would have to divide the X if you want to get it to the other side.

People, it's not 0.9999, a zero then a decimal place then 4 nines, it goes on to infinity, you CANNOT use a calculator!

I'm not using a calculator. I am doing the written math. you get 10x = 9.999.....

so why are you subtracting X? You don't subtract, you divide by 10 to ge tthe X by itself.

because when you do that you are back to x=.9999 :p

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Dazzla    5

I've proven it to you 3 times, explain what's wrong please, without the use of calc.exe...

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bangbang023    31
x = 0.9999...

10x = 9.9999...

10x - x = 9x

9.9999... - 0.9999... = 9

9 = 9x

1 = x = 0.9999...

I think you a made a mistake:

10x = 9.9999

but why subtract x then? that doesn't make sense. You would have to divide the X if you want to get it to the other side.

People, it's not 0.9999, a zero then a decimal place then 4 nines, it goes on to infinity, you CANNOT use a calculator!

I'm not using a calculator. I am doing the written math. you get 10x = 9.999.....

so why are you subtracting X? You don't subtract, you divide by 10 to ge tthe X by itself.

because when you do that you are back to x=.9999 :p

exactly and if x is equal to 0.999... then it's always equal to 0.999.....

x can not be equal to more than one constant. it's mathematically incorrect

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Samoa    0
I've proven it to you 3 times, explain what's wrong please, without the use of calc.exe...

the only thing you have proven is your calculations only fit the misapplication you are failing to see.

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Dazzla    5

bangbang, you're out of your depth, don't bother.

Proof 1:

x = 0.9999...

10x = 9.9999...

10x - x = 9x

9.9999... - 0.9999... = 9

9 = 9x

1 = x = 0.9999...

Proof 2:

0.111... = 1/9

0.111...*9 = 0.999...

since 0.111.... = 1/9 -> 1/9 * 9 = 0.999...

1/9 * 9 = 9/9 = 1

Proof 3:

0.3 recurring = 1/3

0.3 recurring * 3 = 0.9 recurring

1/3 *3 = 1

Disprove...

:sleep:

http://forums.philosophyforums.com/showthr...38&page=1&pp=25

I'm off to bed now, time to unsubscribe and leave you talking to a brick wall...

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Samoa    0
oh my, such a simple proof yet so many confused minds... should i show a 1 = 0 proof? :p

You haven't done anything... :rolleyes:

(edit) sorry I didn't realize you were agreeing with me... :blush:

Edited by Samoa

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un4given1    0

Samoa: I was not saying you were wrong. I was saying that he was wrong.

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bangbang023    31

don't go saying I'm out of "my depth" I know what I am saying. Your second proof is exactly right but your first proof, I feel, is off mathematically. You subtract x from 10x. if you do that you also must subract x from 9.99999.....what ever you do to one side you must do to the other.

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.Atlantis    0

Why all the complicated sums, isn't it just plain and simple, 1 = 1 | .9 recurring = .9 recurring

Infinity 9's doesn't eventually = 1.

-Grant

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Samoa    0
bangbang, you're out of your depth, don't bother.

Proof 1:

x = 0.9999...

10x = 9.9999...

10x - x = 9x

9.9999... - 0.9999... = 9

9 = 9x

1 = x = 0.9999...

Proof 2:

0.111... = 1/9

0.111...*9 = 0.999...

since 0.111.... = 1/9 -> 1/9 * 9 = 0.999...

1/9 * 9 = 9/9 = 1

Proof 3:

0.3 recurring = 1/3

0.3 recurring * 3 = 0.9 recurring

1/3 *3 = 1

Disprove...

x = 0.9999...

10x = 9.9999...

10x - x = 9x you are convienantly leaving off the 9x part of 9*.99999

which equals 8.991

9.9999... - 0.9999... = 9

9 = 9x

1 = x = 0.9999...

in this part 10x - x = 9x

you are convienantly leaving off the 9x part of 9*.99999

which equals 8.991

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bangbang023    31
Why all the complicated sums, isn't it just plain and simple, 1 = 1 | .9 recurring = .9 recurring

Infinity 9's doesn't eventually = 1.

-Grant

well it can when you convert to fractions. Kind of a crude method and no where near scientifically acceptable but you can make it work.

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Dazzla    5
don't go saying I'm out of "my depth" I know what I am saying. Your second proof is exactly right but your first proof, I feel, is off mathematically. You subtract x from 10x. if you do that you also must subract x from 9.99999.....what ever you do to one side you must do to the other.

I did take x from 9.9999....

first I took x from 10x which you agree with, then I took x from 9.9999... leaving 9 which equalled 9x, therefore x = 1 :)

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Dazzla    5
10x - x = 9x  you are convienantly leaving off the 9x part of 9*.99999

which equals 8.991

in this part 10x - x = 9x

you are convienantly leaving off the 9x part of 9*.99999

which equals 8.991

What on earth are you talking about.

10x - x = 9x

That's a statement on it's own and has nothing to do with the numbers at all.

The statement amounts to 9.9 recurring minus 0.9 recurring which equals 9.

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un4given1    0

Dazzla

x = 0.9999... Ok

10x = 9.9999... OK

10x - x = 9x (your math is wrong. first off, where did your trailing 9's go? second if you want to complete the equation it would be 10x/x=9.999.../x which leaves you with 10=9.9999.../x If you divide 9.9999.../.99999... you get 10.000000000000...9 10=10.0000000000000000000...9 this is a false proof!)

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Samoa    0

please explain how 9x equals 1? 9 x .9999 = 8.991

that is the error, the subraction does not make up for the inaccurate calcualtion.

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Dazzla    5

Read my post above yours :rolleyes:

bangbangs got it spot on

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.Atlantis    0
Why all the complicated sums, isn't it just plain and simple, 1 = 1 | .9 recurring = .9 recurring

Infinity 9's doesn't eventually = 1.

-Grant

well it can when you convert to fractions. Kind of a crude method and no where near scientifically acceptable but you can make it work.

Well, isn't that like, bending the rules or finding a way round the truth? I may be wrong I'm no mathematician but geez, How can the number 1 = .9 recurring or vice versa?

If the dinner ladys did that at our school they'd be stealing our money...

-Grant

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bangbang023    31

ahh I see it now. you left out a few steps and I didn't look carefull enough the first time. You're right Dazzla. Sorry man.

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Samoa    0
10x - x = 9x? you are convienantly leaving off the 9x part of 9*.99999

which equals 8.991

in this part 10x - x = 9x

you are convienantly leaving off the 9x part of 9*.99999

which equals 8.991

What on earth are you talking about.

10x - x = 9x

That's a statement on it's own and has nothing to do with the numbers at all.

The statement amounts to 9.9 recurring minus 0.9 recurring which equals 9.

It is all based on numbers...

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Dazzla    5
please explain how 9x equals 1? 9 x .9999 = 8.991

that is the error, the subraction does not make up for the inaccurate calcualtion.

9x DOESN'T equal 1, it equals 9.

10x - x = 9x

At no point do I ever do 9 x .99999..., that's why you go via 10x - x. That's the whole point of the equation!

The statement amounts to 9.9 recurring minus 0.9 recurring which equals 9.

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Dazzla    5
ahh I see it now. you left out a few steps and I didn't look carefull enough the first time. You're right Dazzla. Sorry man.

Good man, now I'm really off to bed, work at 6, bangbang can continue to tutor samoa...

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Samoa    0
please explain how 9x equals 1? 9 x .9999 = 8.991

that is the error, the subraction does not make up for the inaccurate calcualtion.

for crying out loud, someone please explain how

10x-x = 9x YOU cannot subtract the given unit. Dazzla's whole basis for saying .9999 equals 1 is based on that one equation.

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Dazzla    5

Uhh, explain why I can't subtract 0.9 recurring from 9.9 recurring?

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Samoa    0
Uhh, explain why I can't subtract 0.9 recurring from 9.9 recurring?

you can do that. that part is not invalid. your 9x part is.

10x-x=9x

10(.9999) - (.9999) = 9 * (.9999)

9.9999 -.9999 = 8.991

9 = 8.991 that is the flaw