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Need help

  1. Oct 7, 2004 #1
    Find all positive integers c such that it is possible to write c = a/b + b/a with positive integers a and b.
    Please help me :smile:
     
    Last edited: Oct 7, 2004
  2. jcsd
  3. Oct 7, 2004 #2

    shmoe

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    You know [tex]c=\frac{a^2+b^2}{ab}[/tex] is an integer, so [tex]ab[/tex] divides [tex]a^2+b^2[/tex]. What factors must a and b have in common?
     
  4. Oct 7, 2004 #3
    i got c=2 as the answer, is it right?
     
    Last edited: Oct 7, 2004
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