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Length of a complex vector

  1. Feb 28, 2017 #1
    1. The problem statement, all variables and given/known data
    Let a is a complex vector given by

    a = 2π K - i ρ / α^2 ,

    where ρ is a two dimensional position vector and K is the corresponding two dimensional vector in the Fourier space.

    In order to find magnitude of this vector, i found that it is 4π^2 K^2 + ρ^2 / α^4 .
    The logic I used to get my solution is
    (magnitude of a)^2 = a.a*, where * denotes the complex conjugate.

    Please can someone guide me to the correct step by step solution.


    Thanks
     
    Last edited: Feb 28, 2017
  2. jcsd
  3. Feb 28, 2017 #2

    BvU

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    How can it be you have found the magnitude without going through the steps ?
    What's the expression for the magnitude of a vector ?
    What's the expression for the magnitude of a complex number ?
    Are you aware of the PF rules and the guidelines that in fact disallow us to help you if you don't make an attempt at solution ?
     
  4. Feb 28, 2017 #3
    Hi BvU i edited my question and included the formula which I used for getting the answer.
     
  5. Feb 28, 2017 #4

    BvU

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    And the formula did its work, so what is your question ?
     
  6. Feb 28, 2017 #5
    My question is whether the formula I used and the answer I got is correct or my logic has a conceptual mistake?
     
  7. Feb 28, 2017 #6

    BvU

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    I think you are doing fine. For a vector you have the inner product and for a complex number you have the ##|{\bf a}|^2= {\bf aa^*}##.
    (so don't forget to take the square root at the end ... :smile:)
     
  8. Feb 28, 2017 #7
    Thanks for the reply. Yes, I should take the square root at the end.
     
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