April 20th, 2008, 06:38 AM
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Quote:
Originally Posted by ice_syncer  Yeah well, I saw read that article before I posted it,
anyways I did derive a formula by "completing the cube" method, just took 5 minutes, sadly it only works for perfect cubes or cubic equations with one root.
It is ![[-b+ CUBEROOT(-27a^2d+b^3)]/3a](http://www.mathhelpforum.com/math-help/latex2/img/e921fd8062997798d83602f17b7f313f-1.gif "[-b+ CUBEROOT(-27a^2d+b^3)]/3a")
-27a^2d+b^3 is the discriminant, funny part is, the discriminant is always 0 so the actual formula is -b/3a. 
Ice SYnc | There are occasionally neat formulas that work for specific kinds of cubics, but solving one in general is rather difficult. And if you think cubics are bad, you should try quartics!
-Dan
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