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Ktomislav
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 Posted: Wed Sep 24, 2008 7:54 am Post subject: 1 = -1 |
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Maybe some of you already now this.
But I will prove to the rest of you that 1 = - 1. There's something wrong in that, and you have to figure out what is it.
i is an imaginary unit and i? = -1
i? = i * i
-1 = sqrt (-1) * sqrt (-1)
-1 = sqrt (-1 * (-1))
-1 = sqrt (1)
-1 = 1
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Zeroth
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| Posted: Wed Sep 24, 2008 8:26 am Post subject: Re: 1 = -1 |
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| Thats easy. You can't pull the two sqrt(-1)'s together into one sqrt. |
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Ktomislav
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| Posted: Wed Sep 24, 2008 8:32 am Post subject: Re: 1 = -1 |
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Zeroth @ 24.9.2008, 14:26 wrote: Thats easy. You can't pull the two sqrt(-1)'s together into one sqrt.
Yes, that's it. 
And how about this one. This one is easier.
2a-a+2b-b=2c-c
2a+2b+2c=a+b+c
2(a+b+c)=a+b+c
2=1
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jbking
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| Posted: Wed Sep 24, 2008 10:47 am Post subject: Re:1 = -1 |
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| In the second one, there is the point that a+b+c=0 which is why you couldn't divide both sides by that and still have a valid equation. |
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Ktomislav
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| Posted: Wed Sep 24, 2008 10:52 am Post subject: Re: 1 = -1 |
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Yes, that's it. 
You are too smart. 
And you probably new that before.  |
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Zeroth
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| Posted: Wed Sep 24, 2008 11:33 am Post subject: Re: 1 = -1 |
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Theres also the fact that you mixed up some of the signs in the moving of variables.  |
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gitoxa
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| Posted: Wed Sep 24, 2008 9:19 pm Post subject: Re: 1 = -1 |
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My favourite mathematical proof.
x = 0.999...
10x = 9.999...
10x - x = 9.999... - 0.999...
9x = 9
x = 1
1 = 0.999... |
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CodeMonkey2000
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| Posted: Wed Sep 24, 2008 9:35 pm Post subject: Re: 1 = -1 |
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Ktomislav @ Wed Sep 24, 2008 8:32 am wrote: Zeroth @ 24.9.2008, 14:26 wrote: Thats easy. You can't pull the two sqrt(-1)'s together into one sqrt.
Yes, that's it.
And how about this one. This one is easier.
2a-a+2b-b=2c-c
2a+2b+2c=a+b+c
2(a+b+c)=a+b+c
2=1
That's assuming that a+b+c is not equal to zero. So it's not a real proof
@Zeroth I believe you can. But the fallacy in that one was that sqrt has 2 values, +/- and he didn't evaluate both, and assumed positive. |
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Tony
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| Posted: Wed Sep 24, 2008 10:17 pm Post subject: Re: 1 = -1 |
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gitoxa @ Wed Sep 24, 2008 9:19 pm wrote: My favourite mathematical proof.
1 = 0.999...
@Ktomislav -- I was contemplating putting that one up for you, and I guess gitoxa went ahead. Try to find a flaw with that.  |
Tony's programming blog. DWITE - a programming contest. |
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CodeMonkey2000
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| Posted: Wed Sep 24, 2008 10:32 pm Post subject: Re:1 = -1 |
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| I not sure about that one. Real numbers vs. integers? |
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Tony
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r691175002
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| Posted: Thu Sep 25, 2008 12:27 am Post subject: Re: 1 = -1 |
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gitoxa @ Wed Sep 24, 2008 9:19 pm wrote: 1 = 0.999...
There is nothing wrong here. |
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Dan
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| Posted: Thu Sep 25, 2008 1:03 am Post subject: Re:1 = -1 |
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| For thous wondering: http://en.wikipedia.org/wiki/0.999... |
| Computer Science Canada
Help with programming in C, C++, Java, PHP, Ruby, Turing, VB and more! |
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Tony
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| Posted: Thu Sep 25, 2008 9:59 am Post subject: Re:1 = -1 |
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| Thus the emphasis and the winking in the original question. Yes, it was a trick question -- there is no flaw. Although it appears that some might think that there might be. |
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Tony's programming blog. DWITE - a programming contest. |
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Ktomislav
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| Posted: Thu Sep 25, 2008 11:05 am Post subject: Re:1 = -1 |
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Tony @ 25.9.2008, 15:59 wrote: Thus the emphasis and the winking in the original question. Yes, it was a trick question -- there is no flaw. Although it appears that some might think that there might be.
But 1 is not equal to 0.999...
If you use that formula it may be is, but in fact it is not.
It is an exception. (it must be) |
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