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Math Help - Dubious Derivative

  1. #1
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    Dubious Derivative

    If you can spot the error please do not post the explanation let other people have fun solving it. For the first few days. If you do and I see it I will delete it.

    Notice that x^2=x+x+x...+x where x appears x times. Thus, taking the derivative of both sides,
    2x=1+1+1...+1 but 1 appears x times thus, 2x=x? What is wrong?
    Last edited by ThePerfectHacker; January 10th 2006 at 02:59 PM.
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  2. #2
    TD!
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    My lips are sealed, unless we're allowed to post our guess in a 'spoiler' kind of tag? Unvisible unless selected.

    Perhaps another one, spot the error but don't reveal (or reveal covered using white text in a code box for example).

    e^{2\pi i}  = 1 \Leftrightarrow \ln e^{2\pi i}  = \ln 1 \Leftrightarrow 2\pi i = 0
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  3. #3
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    TD! Your problem is connected with my "paradox" I posed here before.

    How did you like the derivative problem?
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    What's the background color used by these boards? We can use it as invisible ink.
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    Quote Originally Posted by Treadstone 71
    What's the background color used by these boards? We can use it as invisible ink.
    I do not know exactly but you can use MS-Paint. They have a color-picker. It is a tools which shows your EXACTLY which color something is.
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  6. #6
    Grand Panjandrum
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    Quote Originally Posted by ThePerfectHacker
    I do not know exactly but you can use MS-Paint. They have a color-picker. It is a tools which shows your EXACTLY which color something is.
    RGB values 245,245,255 apparently.

    RonL
    Last edited by CaptainBlack; January 11th 2006 at 09:43 PM.
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  7. #7
    TD!
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    Quote Originally Posted by ThePerfectHacker
    TD! Your problem is connected with my "paradox" I posed here before.

    How did you like the derivative problem?
    Indeed!

    I've seen the derivative fallacy before
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  8. #8
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    Hex values are F5F5FF. Click on "quote" to see the exact tags.
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  9. #9
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    white is almost invisible

    If you right in white then [you can barely see it] unless you highlight between the brackets.
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  10. #10
    Forum Admin topsquark's Avatar
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    I'll have to remember this as an annoying "proof" of 2=1. I like it!

    -Dan
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