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Thread: find a complex number given modulus of another

  1. February 12th 2010, 03:01 PM #1
    differentiate
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    find a complex number given modulus of another

    If z = x + iy, and the modulus of z is 1, then find:
    \frac{z - 1}{z + 1}
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  2. February 12th 2010, 11:35 PM #2
    CaptainBlack
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    Quote Originally Posted by differentiate View Post
    If z = x + iy, and the modulus of z is 1, then find:
    \frac{z - 1}{z + 1}
    Well, what have you tried?

    To start you off you could try:

    <br /> \frac{z - 1}{z + 1}=\frac{(x-1)+iy}{(x+1)+iy}<br />

    CB
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  3. February 13th 2010, 02:25 AM #3
    HallsofIvy
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    Multiply both numerator and denominator by \overline{z}+ 1.
    A miracle occurs!
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