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#1 2009-01-11 06:11:48

1q2w3e4
Member
Registered: 2009-01-11
Posts: 10

1+1=1

I heard that you can prove that one plus one equals one! How?

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#2 2009-01-12 01:14:33

TheDude
Member
Registered: 2007-10-23
Posts: 361

Re: 1+1=1

You cannot "prove" that 1 + 1 = 1, since it's not true.  You can give a false proof that most people with limited mathematical knowledge would not catch, but it's nothing more than a magic trick.

x = y
x^2 = xy
x^2 - y^2 = xy - y^2
(x + y)(x - y) = y(x - y)
x + y = y
y + y = y
1 + 1 = 1


A good exercise would be to figure out where the mistake in this "proof" is.


Wrap it in bacon

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#3 2009-01-12 01:54:03

Jai Ganesh
Administrator
Registered: 2005-06-28
Posts: 45,967

Re: 1+1=1

1q2w3e4 ,
Are you interesting in knowing where the flaw lies?


It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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#4 2009-01-15 12:43:40

tobi's a good boy
Member
Registered: 2008-08-14
Posts: 32

Re: 1+1=1

1+1=1 is real

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#5 2009-01-15 23:26:32

1q2w3e4
Member
Registered: 2009-01-11
Posts: 10

Re: 1+1=1

And hoe is that?

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#6 2009-01-16 00:06:13

Suyog
Member
Registered: 2009-01-14
Posts: 2

Re: 1+1=1

x = y
x^2 = xy
x^2 - y^2 = xy - y^2  ----------  here 0 = 0
(x + y)(x - y) = y(x - y)  --------  divide by 0 is undetermined down
x + y = y
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