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asnaseer

  • 3 years ago

Puzzle: Who can spot what is wrong here? Theorem: 4 = 5 Proof: -20 = -20 16 - 36 = 25 - 45 4^2 - (9x4) = 5^2 - (9x5) 4^2 - (9x4) + 81/4 = 5^2 - (9x5) + 81/4 (4 - 9/2)^2 = (5 - 9/2)^2 4 - 9/2 = 5 - 9/2 4 = 5

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  1. lgbasallote
    • 3 years ago
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    how did you get -20=-20 from 4=5

  2. Freyes
    • 3 years ago
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    It's a puzzle.

  3. asnaseer
    • 3 years ago
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    The Theorem states 4 = 5 It is then followed by the proof

  4. lgbasallote
    • 3 years ago
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    oh that

  5. Freyes
    • 3 years ago
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    the third to last step

  6. JakeV8
    • 3 years ago
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    sqrt of neg?

  7. asnaseer
    • 3 years ago
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    and what exactly is wrong with that step?

  8. Freyes
    • 3 years ago
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    The step is squaring a negative 1/2 and the other is squaring 1/2

  9. asnaseer
    • 3 years ago
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    which is fine, since (-1/2)^2 = (1/2)^2

  10. Freyes
    • 3 years ago
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    Yes but then the square root of that after is where the problem is

  11. asnaseer
    • 3 years ago
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    correct :)

  12. Freyes
    • 3 years ago
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    you're choosing the positive side

  13. Freyes
    • 3 years ago
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    not the same negative part you're squaring

  14. cwrw238
    • 3 years ago
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    yes - well done frees

  15. asnaseer
    • 3 years ago
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    it is essentially the same as saying: (-1)^2 = (1)^2 therefore -1 = 1

  16. asnaseer
    • 3 years ago
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    well spotted!

  17. oldrin.bataku
    • 3 years ago
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    \[\pm[4-\frac92]=\pm[5-\frac92]\]

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