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Thread: 1$ = 1c... what's wrong?

  1. #1 1$ = 1c... what's wrong? 
    Forum Ph.D. william's Avatar
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    Hi all,
    By now y'all have seen a few 'proofs' lately, each containing a different mathematical error.

    Well, here is another. This one is by far not the most difficult, but it might be a bit fun to ponder.

    Theorem: 1$ = 1c (here c = cents)
    'Proof':
    1$ = 100c
    = (10c)*(10c)
    = (0.1$)*(0.1$)
    = 0.01$
    = 1c
    What's the error here...?

    Have fun.
    Cheers,
    william


    "... the polhode rolls without slipping on the herpolhode lying in the invariable plane."
    ~Footnote in Goldstein's Mechanics, 3rd ed. p. 202
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  3. #2 Re: 1$ = 1c... what's wrong? 
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    Quote Originally Posted by william
    Hi all,
    By now y'all have seen a few 'proofs' lately, each containing a different mathematical error.

    Well, here is another. This one is by far not the most difficult, but it might be a bit fun to ponder.

    Theorem: 1$ = 1c (here c = cents)
    'Proof':
    1$ = 100c
    = (10c)*(10c)
    = (0.1$)*(0.1$)
    = 0.01$
    = 1c
    What's the error here...?

    Have fun.
    Cheers,
    william

    Sorry Will 100c = 10 * 10c NOT 10c * 10C, that would be 100c^2
    Which then means your next line should read
    10(0.1$) = 1$


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  4. #3  
    Forum Ph.D. william's Avatar
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    That didn't take long!
    "... the polhode rolls without slipping on the herpolhode lying in the invariable plane."
    ~Footnote in Goldstein's Mechanics, 3rd ed. p. 202
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  5. #4  
    Forum Sophomore L.E.A.P.'s Avatar
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    Arrgh, billco, next time keep it for yourself, I figured that one out
    (within 2 minutes of thinking)
    P------------y--------------i----------------s
    ------h-------------s----------------c

    Alternate energy... or should we rather say alternate life?

    Are you interested in scientific high school projects? If you are, please contact me!

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  6. #5 math is right, but not physics ;) 
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    Figured out in two seconds. Know that it is in second step. These problems are mathematically correct, but their physics are wrong.
    K. Srinivasa Ramanujam
    M.S (by Research) Scholar,
    http://ramanujamblog.blogspot.com
    India
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  7. #6  
    Forum Freshman lince!'s Avatar
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    agree to sramanujam
    the trick can be guessed when there is unit present in the first line
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  8. #7  
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    Sorry guys I intended to do it as a PM but somehow hit the wrong button!

    Just be thankful I'm not in charge of nuclear missile silos!
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  9. #8  
    Forum Isotope Zelos's Avatar
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    Telephone rings:
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    billco hangs up
    billco: "What were i supposed to do again? Oh yeah press the big red button"
    I am zelos. Destroyer of planets, exterminator of life, conquerer of worlds. I have come to rule this uiniverse. And there is nothing u pathetic biengs can do to stop me

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  10. #9  
    Guest
    Constantly following me around and posting personal insults - which are nothing to do with the thread, do nothing to convince people that you are anything other than childish, Again please keep you insults to personal messages which i can delete without reading or responding to.

    Or you could try and solve the posed problem if you have the ability.
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  11. #10 Re: 1$ = 1c... what's wrong? 
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    Quote Originally Posted by william
    Hi all,
    By now y'all have seen a few 'proofs' lately, each containing a different mathematical error.

    Well, here is another. This one is by far not the most difficult, but it might be a bit fun to ponder.

    Theorem: 1$ = 1c (here c = cents)
    'Proof':
    1$ = 100c
    = (10c)*(10c)
    = (0.1$)*(0.1$)
    = 0.01$

    = 1c
    What's the error here...?

    Have fun.
    Cheers,
    william
    10 cents times 10 cents is NOT 1 CENT!!! :wink:
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