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Homework Help: Complex number question

  1. Mar 18, 2008 #1
    Find z
    Question:
    z^3+i=0
    My attempt:
    z^3=-i
    use z^n=|z|^(n) x e^((i)(n)(theta))
    n = 3
    |z|=1
    theta = -pie/2
    Is this correct?
     
  2. jcsd
  3. Mar 19, 2008 #2
    if z=i

    z^2=-1 z^3=-1*i >>-i
     
  4. Mar 19, 2008 #3

    tiny-tim

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    Science Advisor
    Homework Helper

    … one step at a time …

    Hi Ry122! :smile:

    You must be much more logical, or you'll make mistakes. :frown:

    Do it one step at a time.

    You know z^3=-i.

    So - first step - write -i in the form r.e^(i theta).

    What is it?

    Then divide theta by 3. :smile:

    Oh … and how many different solutions are there? :rolleyes:
     
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