Tuesday, 21 April 2015

real analysis - Show the equivalence x=1 $-ε

Let xR. Show the equivalence x=1ϵ<(x1)<ϵ for all ε>0.



So the first thing I thought to do was to prove both sides ( and ) since this is an equivalence question.



i) To show :




Suppose x=1, we have to show ϵ<(x1)<ϵ for all ϵ>0.



$1
If x=1 then 1<(1+ϵ), ϵ>0



(x1)<ϵ
(xϵ)<1



If x=1 then 1ε<1




Therefore ϵ<0, so ϵ>0.



Then i would go on to prove the side, but i'm not sure if i'm on the right line or not. Would really appreciate the help.

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