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Complex numbers (5+2i)=SQRT(x+iy)

  1. Sep 26, 2004 #1
    How do you evaluate this type of problem:

    (5+2i)=SQRT(x+iy)
     
  2. jcsd
  3. Sep 26, 2004 #2
    Have you considered raising both sides to the power of 2? Or writing both sides in polar form?
     
    Last edited: Sep 26, 2004
  4. Sep 26, 2004 #3
    Yes, but when you do that the i value on the left disappears and you get

    21 = x+iy

    which suggests that there is no imaginary part of the solution (?)


    I haven't tried writing both sides in polar form, i'll try that now
     
  5. Sep 26, 2004 #4
    No, since (5 + 2i)^2 is NOT equal to 5^2 + (2i)^2.

    (5 + 2i)^2 = (5 + 2i)(5 + 2i) = 5*5 + 5*2i + 2i*5 + 2i*2i = 25 + 10i + 10i - 4, etc.
     
  6. Sep 26, 2004 #5
    :blushing: of course :blushing:

    :smile: thanks

    it works fine in polars as well
     
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