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Math Help - Modulus of complex numbers

  1. #1
    Junior Member Fnus's Avatar
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    Modulus of complex numbers

    So, I wasn't there when they went through this in class, and even though I've looked on the internet, I have no idea what to do.
    Help would be greatly appreciated. (:

    Find the modulus of the following complex numbers:

    3+5i

    6-10i

    7-8i

    (3+5i)^3
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  2. #2
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by Fnus View Post
    So, I wasn't there when they went through this in class, and even though I've looked on the internet, I have no idea what to do.
    Help would be greatly appreciated. (:

    Find the modulus of the following complex numbers:

    3+5i

    6-10i

    7-8i
    the modulus of a complex number z = x + iy is given by: |z| = \sqrt{x^2 + y^2}

    example, find the modulus of z = 3 + i \sqrt{7}

    |z| = \sqrt{3^2 + (\sqrt{7})^2} = \sqrt{16} = 4

    that's it


    (3+5i)^3
    another rule: |z^n| = |z|^n

    example, find the modulus of (3 + i \sqrt{7})^3<br />

    Let z = 3 + i \sqrt{7}

    we want |z^3|

    now, |z^3| = |z|^3 = 4^3 = 64

    now try your problems
    Last edited by Jhevon; January 20th 2008 at 02:23 AM.
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