Drexel dragonThe Math ForumDonate to the Math Forum



Search All of the Math Forum:

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.


Math Forum » Discussions » sci.math.* » sci.math.independent

Topic: Rational Numbers/Irrational Numbers
Replies: 29   Last Post: Jun 9, 2012 11:03 AM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Virgil

Posts: 7,760
Registered: 5/14/06
Re: Rational Numbers/Irrational Numbers
Posted: Jan 27, 2007 1:44 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

In article <spOdnWCnC5KKbCfYnZ2dnUVZ_uGjnZ2d@giganews.com>,
"David T. Ashley" <dta@e3ft.com> wrote:

> Anonymous wrote in message
> news:1169874202.106385.326130@v45g2000cwv.googlegroups.com...

> > On Jan 26, 11:36 pm, "David T. Ashley" <d...@e3ft.com> wrote:
> >> "Leo" <newsdon...@hotmail.com> wrote in
> >> messagenews:1169780763.086460.114690@s48g2000cws.googlegroups.com...
> >>

> >> > Which set has more numbers, the set of rational numbers or the set of
> >> > irrational numbers?

> >> Well, the set of irrational numbers has at least twice as many elements
> >> as
> >> the set of rational numbers.
> >>
> >> Think about the following functions:
> >>
> >> f(x) = PI + x
> >> g(x) = PI + PI + x
> >>
> >> Every rational number x can be paired with at least two irrationals.
> >>
> >> So, I'm going to go with "irrational" as being bigger.

> >
> > Right answer. Wrong reason. The rationals are countable. The
> > irrationals are uncountable. The rationals have Lebesgue measure zero.
> > The irrationals in [0,1] have Lebesgue measure 1.

>
> I was just clowning around ... but OK, let's explore your logic.
>
> In order for me to have stated the "wrong" reason, there has to be a
> counterexample where my test fits but where there are not "more".
>
> Please provide a counterexample.


It is also the case that every rational can be "paired" with an infinite
set of rationals, but that does not make the set of rationals larger
than the set of rationals.

Are you aware of Cantor's two proofs that there are more reals than
rationals? With slight modification they also prove more irrationals
than rationals.


Date Subject Author
1/25/07
Read Rational Numbers/Irrational Numbers
Donkey
1/25/07
Read Re: Rational Numbers/Irrational Numbers
William Elliot
1/25/07
Read Re: Rational Numbers/Irrational Numbers
fishfry
1/26/07
Read [] Rational Numbers/Irrational Numbers
William Elliot
1/25/07
Read Re: Rational Numbers/Irrational Numbers
Virgil
1/26/07
Read Re: Rational Numbers/Irrational Numbers
David T. Ashley
1/27/07
Read Re: Rational Numbers/Irrational Numbers
David Marcus
6/9/12
Read Re: Rational Numbers/Irrational Numbers
David T. Ashley
6/9/12
Read Re: Rational Numbers/Irrational Numbers
Peter Webb
6/9/12
Read Re: Rational Numbers/Irrational Numbers
Virgil
1/27/07
Read Re: Rational Numbers/Irrational Numbers
zolaman
1/27/07
Read Re: Rational Numbers/Irrational Numbers
zolaman
1/27/07
Read Re: Rational Numbers/Irrational Numbers
William Elliot
1/27/07
Read Re: Rational Numbers/Irrational Numbers
zolaman
1/27/07
Read Re: Rational Numbers/Irrational Numbers
William Elliot
1/27/07
Read Re: Rational Numbers/Irrational Numbers
David T. Ashley
1/27/07
Read Re: Rational Numbers/Irrational Numbers
William Elliot
1/27/07
Read Re: Rational Numbers/Irrational Numbers
Virgil
1/27/07
Read Re: Rational Numbers/Irrational Numbers
Virgil
6/9/12
Read Re: Rational Numbers/Irrational Numbers
David T. Ashley
6/9/12
Read Re: Rational Numbers/Irrational Numbers
Denis Feldmann
6/9/12
Read Re: Rational Numbers/Irrational Numbers
David T. Ashley
6/9/12
Read Re: Rational Numbers/Irrational Numbers
Virgil
6/9/12
Read Re: Rational Numbers/Irrational Numbers
Dave Seaman
6/9/12
Read Re: Rational Numbers/Irrational Numbers
David T. Ashley
1/27/07
Read Re: Rational Numbers/Irrational Numbers
David Marcus
1/27/07
Read Re: Rational Numbers/Irrational Numbers
Bart Goddard
6/9/12
Read Re: Rational Numbers/Irrational Numbers
Virgil
6/9/12
Read Re: Rational Numbers/Irrational Numbers
David T. Ashley
6/9/12
Read Re: Rational Numbers/Irrational Numbers
Virgil

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2013. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.