Author 
Message 
ZH/Franky

1 = 2
assume that... a = b
(a ^ 2) = ab
(a ^ 2)  ab = 0
2((a ^ 2)  ab) = 0
(a ^ 2)  ab = 2((a^2)  ab)
a(a  b) = 2a(a  b)
(a(a  b)) / (a(a  b)) = (2a(a  b)) / (a(a  b))
1 = 2
I kinda freaked out when I saw this today, until I realized why it happens... if a=b, then ab=0... so the fact that you're dividing both sides by a(a  b) means that you are dividing by zero, thus the parts in bold are invalid (since (n / 0) is an illegal operation).
Anyone else got any more of these kind of equations?

Mon Jan 12, 2009 6:53 pm 


funkyass
"God"
Joined: Tue Jul 27, 2004 11:24 pm Posts: 1128

that statement is a bunch of logic fail long before you get to division. Its the reverse application of Occam's razor. You are supposed to reduce complexity, not increase it.
a = b
ok lets get b on the same side as a, so lets subtract b from both sides.
a  b = 0
at this point we are done, there is nothing more we need to do here. a = b as long as they are the same value.
even if you had a valid reason to multiply both sides by a, the approach is off
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Last edited by funkyass on Mon Jan 12, 2009 8:05 pm, edited 1 time in total.

Mon Jan 12, 2009 7:52 pm 


ZH/Franky

No, assuming that a = b (which of course means that they are both of the same value), everything except the boldhighlighted and underlined parts are valid. It's just once of those neat little tricks: you give them this equation and they are shocked that 1 somehow = 2, until they realize the the division by zero.
I could easily use this to make it look as if 1 = 9999 as well:
(a ^ 2) = ab
(a ^ 2)  ab = 0
9999((a ^ 2)  ab) = 0
(a ^ 2)  ab = 9999((a^2)  ab)
a(a  b) = 9999a(a  b)
(a(a  b)) / (a(a  b)) = (9999a(a  b)) / (a(a  b))
1 = 9999
But of course we know this isn't true; as has been mentioned, it's a mathematical practicaljoke.
Yeah sure occam's razor. Keep things as simple as possible and all that, and use the least amount of assumptions possible, but that wasn't the point here.
It was a necessary step to get to the part where you make it look like 1 = 2.

Mon Jan 12, 2009 8:00 pm 


funkyass
"God"
Joined: Tue Jul 27, 2004 11:24 pm Posts: 1128

you must have sucked at algebra.
there is no reason to multiple both sides by a on the second line, nor is multiplication by 2 on the fourth line. Its not a practical joke, its a meme transmitted by those who never really paid much attention in junior high math.
heck, your proof is proving that.
a=b
a^2 = ab lets multiply by a for no good reason;
2a^2 = 2ab multiply by 2;
2a^2  2ab = 0 get all terms on one side;
2a(ab) = 0 collect like terms;
ab = (0/2a) divide by 2a
a = (0/2a) +b add b;
a = b since zero divided by anything is zero, we can toss (0/2a);
incompetence never leads to a practical joke.
a practical joke is disassembling a teachers car, and reassembling it in their office as a a fully electric vehicle. Shooting your own foot isn't a practical joke.
_________________ Does [Kevin] Smith masturbate with steel wool too?
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Mon Jan 12, 2009 8:15 pm 


ZH/Franky

...I suck at algebra. Heh.
Yeah, ok mum.
Hey, news flash: at no time during my creating this thread did I intend to be serious.
Psst psst: I didn't even create this; I got it from http://forums.xkcd.com/viewtopic.php?f=17&t=8119

Mon Jan 12, 2009 8:29 pm 


DataPath
Lurker
Joined: Wed Jul 28, 2004 1:35 am Posts: 128

it's a classic "proof" to mess with the minds of people who enjoy math.
Every operation performed is perfectly valid  it's just the result of the division by zero that's incorrect.

Mon Jan 12, 2009 9:14 pm 


funkyass
"God"
Joined: Tue Jul 27, 2004 11:24 pm Posts: 1128

there is no division by zero... zero is divided by a number, but nothing is divided by zero anywhere in any proofs in this thread.
it a classic incorrect proof... but for fucks sake understand why its incorrect...
_________________ Does [Kevin] Smith masturbate with steel wool too?
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Mon Jan 12, 2009 9:22 pm 


grinvader
ZSNES Shake Shake Prinny
Joined: Wed Jul 28, 2004 4:15 pm Posts: 5621 Location: PAL50, dood !

Yes there is.
IT'S THE LAST STEP.
He divides left and right by a value that's equal to 0/0.
Hello. Sorry. Have a nice day.
For instance I much prefer the one where it's much more subtly done. I shall go dig for it in case i still have it somewhere.
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Mon Jan 12, 2009 9:54 pm 


ZH/Franky

Please allow me to reiterate:
I FUCKING KNOW IT'S AN INVALID PROOF.
I divide by a(a  b) to * intentionally falsely* get that a = 2a, and thus 1 = 2.
a=b, so ab=0, thus a(ab) = 0, thus n / a(a / b) = infinite, thus at the part where I divide by a(a / b), I am dividing by fucking zero, thus you suck for not either understanding the joke or have a fucking sense of mathematical humour, funkyass.
In my equations, these are the only invalid parts:
(a(a  b)) / (a(a  b)) = (2a(a  b)) / (a(a  b))
1 = 2
But they are SUPPOSED to be invalid, because that's part of the practical joke. I.e. as DataPath has mentioned, "it's a classic "proof" to mess with the minds of people who enjoy math. ". The idea is that the person doesn't notice the division by zero, thus doesn't realize why it falsely comes that 1 = 2. So they think "wtf".
Call it "hidden in plain sight", or whatever, because that's the whole point of mathematical pranks such as this: hiding an error in plain sight to provide a false conclusion in order to fuck with people's minds.
Geez funkyass, you need to learn to lightenup. This mathematicallycorrect stress is not good for you
Last edited by ZH/Franky on Mon Jan 12, 2009 10:05 pm, edited 2 times in total.

Mon Jan 12, 2009 9:57 pm 


grinvader
ZSNES Shake Shake Prinny
Joined: Wed Jul 28, 2004 4:15 pm Posts: 5621 Location: PAL50, dood !

I found my favourite one. It is much more subtle. No dividing by zero bullshit. No sir.
It's actually interesting to find where it fucks up. :)
x²+x+1 = 0
x² = x1
Now we set x != 0
x=11/x
Substitute that in the first equation...
x²  1  1/x +1 = 0
x²  1/x = 0
x² = 1/x
x³ = 1
x = 1 != 0, ok...
Substitute that in the first equation again...
1² + 1 + 1 = 0
3 = 0
Have fun suckers
_________________ 皆黙って俺について来い！！
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Last edited by grinvader on Mon Jan 12, 2009 10:09 pm, edited 2 times in total.

Mon Jan 12, 2009 10:03 pm 


ZH/Franky

Show me.
EDIT:
Ah, there it is. I'll take a look.
EDIT2:
I've been following that and seriously, the error must be quite subtle, with quite being an understatement. It'll take me a while to get this.
Last edited by ZH/Franky on Mon Jan 12, 2009 10:36 pm, edited 2 times in total.

Mon Jan 12, 2009 10:05 pm 


DataPath
Lurker
Joined: Wed Jul 28, 2004 1:35 am Posts: 128

I like the "girls = evil" proof

Mon Jan 12, 2009 10:09 pm 


grinvader
ZSNES Shake Shake Prinny
Joined: Wed Jul 28, 2004 4:15 pm Posts: 5621 Location: PAL50, dood !

That one is actually lawlcorrect.
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Mon Jan 12, 2009 10:12 pm 


ZH/Franky

(there was something unrelated to this discussion previously here, but it was a lie; i was trying to test the "other people are gullible" theory)
HEY GRIN:
x²  1/x = 0
is only true when x = 1At any other time (i.e. if x != 1), the fact that it's x^2  the reciprocal of x (aka 1/x), then
(((x^2)  (1/x))) > 0
There's also the very fact that
x²+x+1 = 0 (your first equation)
is only true if x = 0 (you mention that x != 0, so immediately we know that the first equation is explicitly (and not implicitly) false.
So... what's the prize?
Last edited by ZH/Franky on Mon Jan 12, 2009 11:00 pm, edited 7 times in total.

Mon Jan 12, 2009 10:34 pm 


FirebrandX
Trooper
Joined: Tue Apr 19, 2005 11:08 pm Posts: 376 Location: DFW area, TX USA

I forget how it goes, but there is an equation that 1.999(infinity) is equal to 2. Its probably common knowledge, but I always found it fascinating anyway.

Mon Jan 12, 2009 10:42 pm 


ZH/Franky

We should seriously make a thing of this "find the error" game

Mon Jan 12, 2009 11:02 pm 


grinvader
ZSNES Shake Shake Prinny
Joined: Wed Jul 28, 2004 4:15 pm Posts: 5621 Location: PAL50, dood !

Since when is 0²+0+1 = 0 ? Your prize is my finger at your face and nelson laughing in the background.
You only partially cornered the fallacy of the steps (you got a consequence, not the source). Try harder.
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Mon Jan 12, 2009 11:20 pm 


badinsults
"Your thread will be crushed."
Joined: Wed Jul 28, 2004 1:49 am Posts: 1234 Location: Not in Winnipeg

The second step is only true if a = b = 0. So in reality, all you have proved is 0=0.
There is no point to posting this whole thing. 1 does not equal 2. If you are freaking out about this, it is because you suck at math and logic.
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Mon Jan 12, 2009 11:24 pm 


ZH/Franky

Buh, I give up. Being mathematically correct is not the objective here. Being mathematically inconsistent is the objective (with the intention to confuse the person looking at the puzzle). I do not suck at mathematics and logic.
...shit. Well, I'll dig further into it tomorrow (need sleep).
I honestly don't know how I figured that 0^2 + 0 + 1 = 0.
Last edited by ZH/Franky on Mon Jan 12, 2009 11:50 pm, edited 4 times in total.

Mon Jan 12, 2009 11:38 pm 


funkyass
"God"
Joined: Tue Jul 27, 2004 11:24 pm Posts: 1128

this entire thread is proof to the contrary.
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Mon Jan 12, 2009 11:41 pm 


Deathlike2
ZSNES Developer
Joined: Tue Dec 28, 2004 6:47 am Posts: 6747

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Tue Jan 13, 2009 2:13 am 


h4tred


Tue Jan 13, 2009 2:47 am 


megamanzer0
Regular
Joined: Sat Oct 01, 2005 8:51 pm Posts: 220

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Tue Jan 13, 2009 3:42 am 


sweener2001
Inmate
Joined: Mon Dec 06, 2004 7:47 am Posts: 1751 Location: WA

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Tue Jan 13, 2009 3:48 am 


MisterJones
Trooper
Joined: Fri Jul 30, 2004 6:25 am Posts: 387 Location: Mexico

This step doesn't look right.
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Tue Jan 13, 2009 7:16 am 

