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Math Help - I'm confused by equations and the finite differences between the results

  1. #1
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    I'm confused by equations and the finite differences between the results

    If I have an equation such as 2n2 n 1 then the results of the equation will always be positive. Yet, if I write the results for the equation

    1 4 11 22
    and then take the finite differences, I discover that the number that precedes 1 in the series is 0, and before that there are negatives, which is impossible when considering the function.
    what does this mean?
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  2. #2
    MHF Contributor Siron's Avatar
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    Re: I'm confused by equations and the finite differences between the results

    Quote Originally Posted by ribbie View Post
    If I have an equation such as 2n2 n 1
    What does this mean? ...
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  3. #3
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    Re: I'm confused by equations and the finite differences between the results

    2n squared plus n plus 1 (I copied and pasted from a different program)
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  4. #4
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    Re: I'm confused by equations and the finite differences between the results

    I suggest you show us your finite differences and then explain carefully why you think these mean the equation can take negative values.
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    Re: I'm confused by equations and the finite differences between the results

    Quote Originally Posted by SpringFan25 View Post
    I suggest you show us your finite differences and then explain carefully why you think these mean the equation can take negative values.
    1 4 11 22
    3 7 11
    4 4
    Those are the values for n = 0 to n = 3
    working backwards, I get:
    -5 0 1 4 11 22
    -5 -1 3 7 11
    4 4 4 4
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  6. #6
    Member anonimnystefy's Avatar
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    Re: I'm confused by equations and the finite differences between the results

    hi ribbie

    apparently you didn't subtract correctly because 1-0 ain't -1.the number preceding 1 is 2 and not 0.
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  7. #7
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    Re: I'm confused by equations and the finite differences between the results

    Quote Originally Posted by anonimnystefy View Post
    hi ribbie

    apparently you didn't subtract correctly because 1-0 ain't -1.the number preceding 1 is 2 and not 0.
    Indeed, spotted the mistake.
    Thanks to all...
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