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0.9999999999999... = 1 proof!

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Einsteinmc2300

PostPosted: Fri Sep 14, 2007 5:06 pm


ok here is how 0.9... equals 1

1/3= 0.3.....

2/3= 0.6.....

1=3/3=0.9... ! lol right there!


another proof would be trying to reduce 9.999..... into a rational number

10x= 9.999...
x= 0.999...
_____________
9x=9
x=1


so therefore look back in the equation, see that part where it says that x=0.999...?

well x=1 so 1=0.999... biggrin
PostPosted: Wed Oct 10, 2007 12:26 pm


SS4 Gogeta Forever
ok here is how 0.9... equals 1

1/3= 0.3.....

2/3= 0.6.....

1=3/3=0.9... ! lol right there!


another proof would be trying to reduce 9.999..... into a rational number

10x= 9.999...
x= 0.999...
_____________
9x=9
x=1


so therefore look back in the equation, see that part where it says that x=0.999...?

well x=1 so 1=0.999... biggrin


I can't agree with you on that. 3/3 = 1 but 3/3 =/= o.9rep.

So the top one is false. Sorry.

Next.

What? 10x=0.9rep. I got that. Then x=0.9rep? How?

I can say that 1=x and 81=x, but those are two different x's. What you 'splain'd didn't make sense. Sorreh.

Xynene


Zaxoth Arturos

PostPosted: Wed Oct 10, 2007 12:59 pm


Xynene
SS4 Gogeta Forever
ok here is how 0.9... equals 1

1/3= 0.3.....

2/3= 0.6.....

1=3/3=0.9... ! lol right there!


another proof would be trying to reduce 9.999..... into a rational number

10x= 9.999...
x= 0.999...
_____________
9x=9
x=1


so therefore look back in the equation, see that part where it says that x=0.999...?

well x=1 so 1=0.999... biggrin


I can't agree with you on that. 3/3 = 1 but 3/3 =/= o.9rep.

So the top one is false. Sorry.

Next.

What? 10x=0.9rep. I got that. Then x=0.9rep? How?

I can say that 1=x and 81=x, but those are two different x's. What you 'splain'd didn't make sense. Sorreh.
>.> He's not me.

But he'd put 10x=9.9rep, which would then be x=0.9rep.

Anyway, the idea that 0.9rep=1 is a theory in Calculus. But I prefer not to touch it.
PostPosted: Mon Nov 12, 2007 9:56 am


SS4 Gogeta Forever
10x= 9.999...
x= 0.999...
_____________
9x=9
x=1
I cant see how this works either

xXx White Lily xXx


Drake_XIV

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PostPosted: Sat Nov 24, 2007 9:46 am


xXx White Lily xXx
SS4 Gogeta Forever
10x= 9.999...
x= 0.999...
_____________
9x=9
x=1
I cant see how this works either
Someone is gonna kill you...


I do...kinda

...that is either yourself or your spouse.
PostPosted: Mon Dec 03, 2007 9:33 pm


1/9 = .1111111111...


If you multiply all by nine what do you get?

9 * 1/9 is obviously 9/9 = 1

.1111111111... * 9, when done in the traditional multiplication set up should just give you nine times one over and over again, behind the decimal or

.9999999....

So, we have then that

1/9 = .11111111...

9 * 1/9 = 9 * .1111111111

9/9 = .999999999...

1=1

It is true, no matter which way you look at it. I could prove it using calculus if you wanted...but I might as well just leave that to the wikipedia article. If you're interested there is a whole article on this, and why it is true.

IcarusDream


NinjaDude007

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PostPosted: Thu Dec 13, 2007 3:10 pm


IcarusDream
1/9 = .1111111111...


If you multiply all by nine what do you get?

9 * 1/9 is obviously 9/9 = 1

.1111111111... * 9, when done in the traditional multiplication set up should just give you nine times one over and over again, behind the decimal or

.9999999....

So, we have then that

1/9 = .11111111...

9 * 1/9 = 9 * .1111111111

9/9 = .999999999...

1=1

It is true, no matter which way you look at it. I could prove it using calculus if you wanted...but I might as well just leave that to the wikipedia article. If you're interested there is a whole article on this, and why it is true.

I think I get what he's saying... <_<;;; *flees to figure out his own math issue*
PostPosted: Thu Dec 13, 2007 9:41 pm


NinjaDude007

I think I get what he's saying... <_<;;; *flees to figure out his own math issue*
Until you get into Calculus, or unless you're going to study things that correlate to quantum physics, you don't really have to worry about understanding this proof..

Zaxoth Arturos


Azaryth

PostPosted: Mon Feb 25, 2008 1:00 pm


xXx White Lily xXx
SS4 Gogeta Forever
10x= 9.999...
x= 0.999...
_____________
9x=9
x=1
I cant see how this works either


It's subtraction. 9.9999... minus .99999... is 9, and 10x - x is 9x. My math teacher showed us that proof once when she ran out of stuff to do.
PostPosted: Wed Feb 27, 2008 11:00 pm


My mind just exploded.

But I guess thats kind of saying something like:

If I drop this bottle from my hand, it will keep going half way, half way, half way, but never touching the floor. But in reality, it really does. Math blows my mind! MATH IS POWER! haha *nerd8 rolleyes

magnumsama


Ichiro Yamato
Captain

PostPosted: Thu Feb 28, 2008 12:38 pm


You know how much simple math is devoid of the laws of reality?


I mean, you don't HONESTLY believe that s(t) = a*t^2 + v0*t + s0 (Position function for objects in Free Fall) is ever true in reality, or that F(grav) = g*m1*m2 / d^2 (Newton's Universal Law of Gravitation) holds the far reaches of space together?

Because they don't.


Back on topic, there's a more difficult-to-reject proof to the whole matter. Sure simple algebra can seem to prove, but people can raise objections to specific cases that wouldn't prove to be 100% true - that's probably due to the fact that the variable involved remains ambiguous. But, the algebraic proof is pretty much workable for most of the modern world.

However, if you want to get down and dirty with some of the proofs involved, here's one you can try to figure out.

You know how numbers are composed of right? Ever since ... 1st grade? You've learned that multiple-digit numbers belong to categories like, ones digit, tens digit, hundreds digit, and so on.

Meaning: 2530 is basically 2 * 1000 + 5 * 100 + 3 * 10 + 0 * 1
or 2 * (10^3) + 5 * (10^2) + 3 * (10^1) + 0 * (10^0)


Got that so far right?
So what is 0.75? 0 * (1/10)^0 + 7 * (1/10)^1 + 5 * (1/10)^2

That means...
0.999 is 0 * (1/10)^0 + 9 * (1/10)^1 + 9 * (1/10)^2 + 9 * (1/10)^3

User Image - Blocked by "Display Image" Settings. Click to show.

This can be rewritten as an infinite series.

User Image - Blocked by "Display Image" Settings. Click to show.

As you apply the generic ideas of (2nd year) calculus, I'm sure you'll be able to easily see how it all simplifies out.
PostPosted: Wed Mar 05, 2008 6:53 pm


here you go... for those total inept at math... a simple explination....

what is 1 - .9999999...?

the answer is 0.00000... (infinite) you never reach the final .001 because there are an infinite number of zeros

its not the real proof... but it proves the point, if you understand math, go ahead and look at the proofs already posted... they are very nicely layed out 3nodding

Aiusagi
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Einsteinmc2300

PostPosted: Tue Jul 01, 2008 8:49 pm


xXx White Lily xXx
SS4 Gogeta Forever
10x= 9.999...
x= 0.999...
_____________
9x=9
x=1
I cant see how this works either
lol i love xkcd!
PostPosted: Thu Feb 04, 2010 2:28 pm


In a technical sence I understant it since if you had something and .999999999999999999999999999999 of its matter kind of rubbed off (Lets say it was something like a stone so a litte bit of it roughed off) you would still see it as one whole.

Syr-Caffeine

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