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Math Help - Another complex number question:

  1. #1
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    Another complex number question:

    "If z=cis(), find the argument and modulus of 1-z"
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  2. #2
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    Quote Originally Posted by karldiesen View Post
    "If z=cis(), find the argument and modulus of 1-z"
    Let's say that \phi \ne 0.

    Then because 1-\cos(\phi)>0 implies \arg(1-z)=\arctan\left(\frac{\sin(-\phi)}{1-\cos(\phi)}\right).
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  3. #3
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    Quote Originally Posted by karldiesen View Post
    "If z=cis(), find the argument and modulus of 1-z"
    Do you know what "cis" means? If so you can write z in the form "a+ bi", subtract from 1 and then find the argument and modulus of that.
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