Tuesday, March 10, 2009

Cube-Roots

The mathmaticians agreed that every number has 3 cube roots.
But like 8, or 216, it seems that there's only 1 cube root.
But there is still 3, unless it is a perfect cube, in the form of

a3+3a2b+3ab2+b3,

where the roots can overlap, or be the same number. Now, having that said, find all 3 cube roots of 27 (and no, it is not a perfect cube so it has 3 cube roots).

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4 Comments:

Anonymous Anonymous said...

3,-3/2+3sqrt(3)i/2,-3/2-3sqrt(3)i/2

March 10, 2009 7:07 PM  
Blogger Ragknot said...

3

-3(-1)^1/3

3(-1)^2/3

March 10, 2009 7:50 PM  
Blogger Ragknot said...

retry

-3*(-3)^(1/3)
3*3^(1/3)
3*(-1)^(2/3)*3^(1/3)

March 10, 2009 9:06 PM  
Anonymous Anonymous said...

3, 3*cis(2*pi/3), 3*cis(4*pi/3). they are roots of unity. they are the same distance from 0, but differ by 2*pi/3 radians on the complex number plane.

March 28, 2009 1:42 PM  

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