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    mmvv2715's Avatar
    mmvv2715 Posts: 1, Reputation: 1
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    #1

    Dec 1, 2009, 12:55 AM
    finding the roots of a complex equation
    Hi,
    can you please tell me how can I fin the roots of x=(-j)^(1/3)
    ebaines's Avatar
    ebaines Posts: 12,131, Reputation: 1307
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    #2

    Dec 1, 2009, 09:14 AM

    To evaluate this use D'Moivre's theorem:



    So:


    where k = 0, 1, or 2

    This gives three unique roots, each spaced at 120 degrees around the origin. The first is j (you can verify this by evaluating j^3 and see if it equals -j). Can you now determine the other two?
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