## 2 + 2 = 5

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Immortal_Z
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### 2 + 2 = 5

it's possible, mathematically. you get to try to prove it. bonus points if you get the reference x)

I'll prove it when everyone gives up
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Pero
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### Re: 2 + 2 = 5

Spoiler:
Equivalence modulo 1?

Edit: Whoops, forgot to spoiler.
Last edited by Pero on Thu May 08, 2008 4:12 am UTC, edited 2 times in total.

Immortal_Z
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### Re: 2 + 2 = 5

I haven't the slightest what that is x)
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markfiend
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### Re: 2 + 2 = 5

Spoiler:
Rounding errors?

2.4 + 2.4 = 4.8

Round each term to 1 significant figure:
2 + 2 = 5
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thc
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### Re: 2 + 2 = 5

"2+2=5 for extremely large values of 2"

antonfire
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### Re: 2 + 2 = 5

In before
Spoiler:
division by zero. And square roots.
Jerry Bona wrote:The Axiom of Choice is obviously true; the Well Ordering Principle is obviously false; and who can tell about Zorn's Lemma?

Robin S
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### Re: 2 + 2 = 5

Spoiler:
Lemma: 0 = 1 (proof left to the reader)
As a direct consequence of our lemma, it is obvious that 2 + 2 = 2 + 2 + 0 = 2 + 2 + 1 = 5.
This is a placeholder until I think of something more creative to put here.

lingomaniac88
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### Re: 2 + 2 = 5

Spoiler:
Proof of Robin S's lemma:

Let [imath]x[/imath] be a non-zero number, and set [imath]y=x[/imath]. Thus:

$\begin{eqnarray} x &=& y \\ x^2 &=& xy \\ x^2-y^2 &=& xy-y^2 \\ (x+y)(x-y) &=& y(x-y) \\ x+y &=& y \\ 2y &=& y \\ 2 &=& 1 \\ 1 &=& 0 \end{eqnarray}$
"It is common sense to take a method and try it. If it fails, admit it frankly and try another. But above all, try something."
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Blatm
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### Re: 2 + 2 = 5

Spoiler:
The "+1" is silent.

Felstaff
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### Re: 2 + 2 = 5

Spoiler:
two plus two has always been five. We've always been at war with Eastasia
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ehntoo
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### Re: 2 + 2 = 5

Spoiler:
2+2=5 for very small values of 5. xD

Immortal_Z
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### Re: 2 + 2 = 5

lingomaniac wins, but not through the method that I had found. mark twain/samuel clements was where this topic came from, in a letter to an inlaw or something. If that helps anyone, feel free
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Blatm
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### Re: 2 + 2 = 5

Immortal_Z wrote:lingomaniac wins, but not through the method that I had found. mark twain/samuel clements was where this topic came from, in a letter to an inlaw or something. If that helps anyone, feel free

Spoiler:
All he did was divide by zero, which you can't do, mathematically. This false proof is a well known trick. See http://forums.xkcd.com/viewtopic.php?f=17&t=8119 for many more, more interesting false proofs.

Immortal_Z
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### Re: 2 + 2 = 5

though, given that they are variables, why is it not possible to do that? To only divide the group of variables, not what they come out to. Similar to simplifying variable filled fraction problems
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phlip
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### Re: 2 + 2 = 5

Because "ab = ac" doesn't simplify to "b = c". It simplifies to "b = c or a = 0".

So if you know that "a = 0" is true (or even could be true), then you can't deduce "b = c" in general.

0*2 = 0*3, but it doesn't follow that 2 = 3.

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enum ಠ_ಠ {°□°╰=1, °Д°╰, ಠ益ಠ╰};void ┻━┻︵​╰(ಠ_ಠ ⚠) {exit((int)⚠);}
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Immortal_Z
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### Re: 2 + 2 = 5

ah. i admit defeat. thanks x)
An Angel who did not so much Fall as Saunter Vaguely Downwards

afarnen
Posts: 157
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### Re: 2 + 2 = 5

Spoiler:
1/3 = 0.333... multiplied by three
3/3 = 0.999... same as
1 = 0.999... minus 0.999...
0.000...1 = 0 divided by 0.000...1
1 = 0 i did it

QED
Last edited by afarnen on Wed May 14, 2008 4:43 am UTC, edited 1 time in total.

Mathmagic
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### Re: 2 + 2 = 5

afarnen wrote:
Spoiler:
1/3 = 0.333... multiplied by three
3/3 = 0.999... same as
1 = 0.999... minus 0.999...
0.000...1 = 0 divided by 0.000...1
1 = 0 i did it

Please tell me this is a joke.
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afarnen
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### Re: 2 + 2 = 5

mathmagic wrote:
afarnen wrote:
Spoiler:
1/3 = 0.333... multiplied by three
3/3 = 0.999... same as
1 = 0.999... minus 0.999...
0.000...1 = 0 divided by 0.000...1
1 = 0 i did it

Please tell me this is a joke.

NEVER! But yeah, the whole point-nine-repeating equals one thing has been around for a while: http://en.wikipedia.org/wiki/0.999...#Fractions

hermaj
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### Re: 2 + 2 = 5

A) I think I can safely speak for all of us when I say that we are NOT getting into another 0.999... = 1 thing again. Do not even think about it. Do not even hope.

B) I will also take this opportunity to register my minor disappointment that this thread has nothing to do with Radiohead, unless I can hold the desperate hope that that is the reference for which I will get bonus points. Bonus points will appease me.

afarnen
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### Re: 2 + 2 = 5

hermaj wrote:A) I think I can safely speak for all of us when I say that we are NOT getting into another 0.999... = 1 thing again. Do not even think about it. Do not even hope.

B) I will also take this opportunity to register my minor disappointment that this thread has nothing to do with Radiohead, unless I can hold the desperate hope that that is the reference for which I will get bonus points. Bonus points will appease me.

hehe i thought about adding that to my post. two and two always equals fiiiive

Mathmagic
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### Re: 2 + 2 = 5

afarnen wrote:
mathmagic wrote:
afarnen wrote:
Spoiler:
1/3 = 0.333... multiplied by three
3/3 = 0.999... same as
1 = 0.999... minus 0.999...
0.000...1 = 0 divided by 0.000...1
1 = 0 i did it

Please tell me this is a joke.

NEVER! But yeah, the whole point-nine-repeating equals one thing has been around for a while: http://en.wikipedia.org/wiki/0.999...#Fractions

Yes, I am quite familiar with the 0.999...= 1 "debate" for a long time. You'd be surprised at how many people think they can shove a '1' onto the end of an infinitely repeating decimal.
Axman: That, and have you played DX 10 games? It's like having your corneas swabbed with clits made out of morphine.
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afarnen
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### Re: 2 + 2 = 5

mathmagic wrote:
afarnen wrote:
mathmagic wrote:
afarnen wrote:
Spoiler:
1/3 = 0.333... multiplied by three
3/3 = 0.999... same as
1 = 0.999... minus 0.999...
0.000...1 = 0 divided by 0.000...1
1 = 0 i did it

Please tell me this is a joke.

NEVER! But yeah, the whole point-nine-repeating equals one thing has been around for a while: http://en.wikipedia.org/wiki/0.999...#Fractions

Yes, I am quite familiar with the 0.999...= 1 "debate" for a long time. You'd be surprised at how many people think they can shove a '1' onto the end of an infinitely repeating decimal.

well, was my proof any less real than lingomaniac88's?

lingomaniac88 wrote:
Spoiler:
2y = y
2 = 1

Mathmagic
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### Re: 2 + 2 = 5

I think it's a little less egregious an error to have a sly divide-by-zero than to show an infinitely repeating decimal terminate with a 1 at the digit "at infinity".

But no, both proofs were erroneous.
Axman: That, and have you played DX 10 games? It's like having your corneas swabbed with clits made out of morphine.
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phlip
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### Re: 2 + 2 = 5

Well, since they're both divisions by zero, they're both about as bad as each other... and afarnen's was funnier.

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SlyReaper
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### Re: 2 + 2 = 5

Permute:
1 -> 1
2 -> 2
3 -> 3
4 -> 5
5 -> 4

And you're done.

Alternatively, apply Lebadevinski's Inequality to the set of Boromian fields, and expand out by Gregorinov's power series. The answer should pop straight out. (Exercise)

What would Baron Harkonnen do?

Luppoewagan
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### Re: 2 + 2 = 5

let's make this up as I go along.

sin(0) = 1
sin(2π) = 1
0 = 2π
0 = 1 :: division by 2π

Dobblesworth
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### Re: 2 + 2 = 5

Slightly inspired by Portal,

4 + 4 = 10base8
(divide both sides by 2)
2 + 2 = 5
[I don't think it would work like that though. Most likely 2 + 2 = 4base8, but for the purpose of this thread I am disregarding a few laws here and there.]

Sungura
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### Re: 2 + 2 = 5

2 + 2 = 5

Spoiler:
Because Big Brother said so!
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Luppoewagan
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### Re: 2 + 2 = 5

amysrabbitranch wrote:2 + 2 = 5

Spoiler:
Because Big Brother said so!

What do you mean? 2+2 has always been 5. Big Brother simply alerted us to our previous errors, which were utterly wrong.

vqcg
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### Re: 2 + 2 = 5

amysrabbitranch wrote:2 + 2 = 5

Spoiler:
Because Big Brother said so!

What do you mean? 2+2 has always been 5. Big Brother simply alerted us to our previous errors, which were utterly wrong.

Not AWAYS!
2 and 2 are sometimes 5. Sometimes they are three. Sometimes they are both of them at once.
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phlip
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### Re: 2 + 2 = 5

No, 2+2 has always been 5 and always will be 5. Any memories you may have of it being 3 are false, planted there by the Eurasians (who are our enemies, and always have been).

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enum ಠ_ಠ {°□°╰=1, °Д°╰, ಠ益ಠ╰};void ┻━┻︵​╰(ಠ_ಠ ⚠) {exit((int)⚠);}
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eddiekizer
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### Re: 2 + 2 = 5

Felstaff:

We have always been at war with Eurasia.
Minitruth requires you to change your post.

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Sungura
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### Re: 2 + 2 = 5

vqcg wrote:
amysrabbitranch wrote:2 + 2 = 5

Spoiler:
Because Big Brother said so!

What do you mean? 2+2 has always been 5. Big Brother simply alerted us to our previous errors, which were utterly wrong.

Not AWAYS!
2 and 2 are sometimes 5. Sometimes they are three. Sometimes they are both of them at once.

2 + 2 = 5 on Thursdays, and 3 on Saturdays.
"Would you rather fight a Sungura-sized spider or 1000 spider-sized Sunguras?" -Zarq
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Game_boy
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### Re: 2 + 2 = 5

The Reaper wrote:Evolution is a really really really long run-on sentence.

ginnybee
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### Re: 2 + 2 = 5

In addition, there are 5 lights.

markfiend
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### Re: 2 + 2 = 5

lingomaniac88 wrote:
Spoiler:
Proof of Robin S's lemma:

Let [imath]x[/imath] be a non-zero number, and set [imath]y=x[/imath]. Thus:

$\begin{eqnarray} x &=& y \\ x^2 &=& xy \\ x^2-y^2 &=& xy-y^2 \\ (x+y)(x-y) &=& y(x-y) \\ x+y &=& y \\ 2y &=& y \\ 2 &=& 1 \\ 1 &=& 0 \end{eqnarray}$

I prefer:
Spoiler:
$\begin{eqnarray} x &=& 1 \\ x-1 &=& 0 \\ x^2-1 &=& 0 \\ x^2-1 &=& x-1 \\ (x+1)(x-1) &=& x-1 \\ x+1 &=& 1 \\ x &=& 0 \\ 1 &=& 0 \end{eqnarray}$
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Actaeus
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### Re: 2 + 2 = 5

This is clearly an example of emergent attributes.
Ever heard of the phrase "greater than the sum of its parts"? This is an example.
Strict reductionists, of course, would reject the idea.

DarkLordofSquirrels
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### Re: 2 + 2 = 5

ginnybee wrote:In addition, there are 5 lights.

Even Picard would have to agree that if 2 +2 = 5, there are five lights.

If we say that the symbol "5" is a variable, then the equation has a solution when 4 = 5.

@markfiend: Yours isn't as fun, because it squares x-1 = 0 and gets x^2-1=0, which as we all know is even sillier than dividing by zero

Token
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### Re: 2 + 2 = 5

DarkLordofSquirrels wrote:@markfiend: Yours isn't as fun, because it squares x-1 = 0 and gets x^2-1=0, which as we all know is even sillier than dividing by zero

No, it doesn't. That just follows from the first line. It makes the exact same division by zero error as every other proof like it.
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