Results 1 to 2 of 2

Thread: Inverse of irrational number

  1. #1
    Apr 2009

    Inverse of irrational number


    How do I prove that the inverse of an irrational number is irrational? I'm stumped.

    Thanks for any help with this.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Mar 2007


    By "inverse", do you mean "reciprocal"? If so, then you might proceed by contradiction:

    Assume that x is irrational, with reciprocal 1/x = y. Suppose y is rational, so y = p/q for some integers p and q. Then 1/y = q/p = x, so...

    How does that end?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 4
    Last Post: Apr 28th 2011, 06:20 AM
  2. Irrational number
    Posted in the Number Theory Forum
    Replies: 2
    Last Post: Feb 27th 2010, 11:24 AM
  3. Replies: 0
    Last Post: Feb 16th 2010, 05:04 AM
  4. Replies: 5
    Last Post: Oct 7th 2008, 12:55 PM
  5. More Irrational Number ??>
    Posted in the Algebra Forum
    Replies: 13
    Last Post: Jul 31st 2005, 11:55 AM

Search Tags

/mathhelpforum @mathhelpforum