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Homework Help: Finding the modulus

  1. Jan 10, 2012 #1
    1. The problem statement, all variables and given/known data
    Find the modulus for:
    (3 - 4i)^10/(2 - i)^8

    2. Relevant equations

    3. The attempt at a solution
    I tried putting the two terms in their exponential forms. Then do simple exponential operations and convert back to cartesian form to get the modulus.
    3 - 4i = [itex]5e^{arctan(-4/3)}[/itex]
    2 - i = [itex]\sqrt{5}e^{arctan(1/2)}[/itex]

    However the arguments aren't going to be exact numbers. Is there another way to approach this question?
  2. jcsd
  3. Jan 10, 2012 #2


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    Science Advisor
    Homework Helper

    You left out an i on your exponents in polar form. But that's besides the point. Don't you think modulus of 3-4i would just be 5? Why or why not?
  4. Jan 10, 2012 #3
    Right. I confused the definition of Modulus with Conjugate. Man, I feel stupid.

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