# please help me

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• August 8th 2009, 11:45 PM
geo2
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???
• August 9th 2009, 05:39 AM
CaptainBlack
Quote:

Originally Posted by geo2
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???

$
(2+i)(2-i)=4+1=5 \notin S
$

CB