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Complex variables

  1. Nov 12, 2009 #1
    Hi,

    I need two simple proofs of complex inequalities.

    1) |1-z|/|z|<2

    2)|1+z|/|z|>1/2

    Ik need them for a bound of a complex integral.It's not homework

    Thank you
     
  2. jcsd
  3. Nov 12, 2009 #2

    Redbelly98

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    Both inequalities are false, hence cannot be proven.

    Try z=0.1 in (1).
    Try z=-1 in (2).
     
  4. Nov 12, 2009 #3
    Hi,

    yes you are right.

    But it's my fault,I forgot something.

    I have to show this inequalities for z->infinity as a lower and upper bound in a complex

    integral.

    Sorry
     
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