1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Complex Number Question

  1. Jul 30, 2009 #1
    [tex]z=x+yi[/tex] determine the values of x and y such that [tex]z=\sqrt{3+4i}[/tex]

    I'm not even sure where to start with this one, so any help would be greatly appreciated
  2. jcsd
  3. Jul 30, 2009 #2
    So basically the question you are given is find x and y where
    [tex] x+yi=\sqrt{3+4i}[/tex].
    Start off by squaring both sides, then go about solving for x and y. When solving variables with complex numbers, you usually equate the real and imaginary parts of both sides. In other words, if you have x+iy=u+iv, then x=u and y=v. This should get you going. Let us know if you are still stuck.
  4. Jul 30, 2009 #3


    User Avatar
    Science Advisor

    In other words, find the square root of 3+4i. Of course, there are two square roots - the problem said "values"- so n!kofeyn's equations will have two solutions. You could also do this problem by converting to "polar" form and applying deMoivre's formula. That was my first thought but n!kofeyn's idea is simpler and more straightforward.
  5. Jul 30, 2009 #4
    Awesome. I've got it now. Thanks for your help.
  6. Jul 30, 2009 #5
    No problem.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook