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Math Help - How to derive sum of cubes formula?

  1. #1
    undead_yogurt
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    Question How to derive sum of cubes formula?

    How do you derive:

    A^3 + B^3 = (A+B)(A^2-AB+B^2)


    Thanks!
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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by undead_yogurt
    How do you derive:

    A^3 + B^3 = (A+B)(A^2-AB+B^2)


    Thanks!
    It is obvious that

    A\ =\ -B
    is a root of

    A^3\ +\ B^3
    then synthetic division division of

    A^3\ +\ B^3
    by

    A\ +\ B
    will give the second factor on the right.

    Alternativly you could just multiply out

    (A+B)(A^2-AB+B^2)
    to get

    A^3\ +\ B^3
    RonL
    Last edited by CaptainBlack; November 30th 2005 at 01:58 PM.
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