How do you derive:

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

Thanks!

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- Oct 31st 2005, 08:52 PMundead_yogurtHow to derive sum of cubes formula?
How do you derive:

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

Thanks! - Nov 30th 2005, 12:51 PMCaptainBlackQuote:

Originally Posted by**undead_yogurt**

$\displaystyle A\ =\ -B$is a root of

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

$\displaystyle A^3\ +\ B^3$by

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

Alternativly you could just multiply out

$\displaystyle (A+B)(A^2-AB+B^2)$to get

$\displaystyle A^3\ +\ B^3$RonL