Results 1 to 1 of 1

Math Help - PROOF by counterexample

  1. #1
    Junior Member mremwo's Avatar
    Joined
    Oct 2010
    From
    Tampa, FL
    Posts
    53

    PROOF by counterexample

    give a counterexample for each of the two
    directions of:

    The product xy of a rational number x and a real number y is irrational if
    and only if y is irrational.

    cant figure out the first direction
    Last edited by mremwo; October 4th 2010 at 05:12 PM. Reason: actually i want to know how to EITHER give a counterexample OR proveone/ both directions
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Counterexample
    Posted in the Discrete Math Forum
    Replies: 3
    Last Post: September 26th 2010, 10:17 AM
  2. Replies: 2
    Last Post: September 8th 2010, 01:27 AM
  3. Replies: 1
    Last Post: March 1st 2010, 09:24 PM
  4. Counterexample
    Posted in the Differential Geometry Forum
    Replies: 0
    Last Post: October 28th 2009, 04:06 PM
  5. A counterexample
    Posted in the Number Theory Forum
    Replies: 0
    Last Post: November 1st 2006, 10:06 AM

/mathhelpforum @mathhelpforum