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Math Help - please help me

  1. #1
    Newbie
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    Aug 2009
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    please help me with this..

    prove that S={2a+bi:a,b ε Z} is not closed multiplication where i= √1???

    and with that

    Find the continued fraction expansion of √8 and hence or otherwise show that √8

    is irrational???
    Last edited by mr fantastic; August 9th 2009 at 02:20 AM. Reason: Merged posts
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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by geo2 View Post
    please help me with this..

    prove that S={2a+bi:a,b ε Z} is not closed multiplication where i= √1???

    and with that

    Find the continued fraction expansion of √8 and hence or otherwise show that √8

    is irrational???
     <br />
(2+i)(2-i)=4+1=5 \notin S<br />

    CB
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