Results 1 to 4 of 4

Math Help - Rationalise and Simplify

  1. #1
    Newbie
    Joined
    Oct 2010
    Posts
    7

    Rationalise and Simplify

    Guys,

    I recently got a practice problem to try based on something or other I did a few years back in school. Thought I could handle it but apparently not:

    Rationalise the denominator of, and thus simplify the expression

    \frac{2\sqrt{2}}{4-\sqrt{14}}           -2\sqrt{7}




    Now I whats getting me is the 4 - root 14 in the denominator. If it were simply root 14 I would be able to rationalise and simplify no problem.

    Thanks.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor harish21's Avatar
    Joined
    Feb 2010
    From
    Dirty South
    Posts
    1,036
    Thanks
    10
     \displaystyle \frac{2\sqrt{2}}{4-\sqrt{14}} -2\sqrt{7} =  \left[\dfrac{2\sqrt{2}}{4-\sqrt{14}} \times \frac{4+\sqrt{14}}{4+\sqrt{14}}\right] -2\sqrt{7}

    simplify and finish.. Can you?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Oct 2010
    Posts
    7
    I got a bit further but hit another jam.

    I got to

    \frac{4\sqrt{7}}{-14+4\sqrt{14}} -2\sqrt{7}
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor harish21's Avatar
    Joined
    Feb 2010
    From
    Dirty South
    Posts
    1,036
    Thanks
    10
    No...


    \left[\dfrac{2\sqrt{2}}{4-\sqrt{14}} \times \dfrac{4+\sqrt{14}}{4+\sqrt{14}}\right]

    = \dfrac{8\sqrt{2}+2\sqrt{28}}{16-14}
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Rationalise
    Posted in the Algebra Forum
    Replies: 1
    Last Post: February 3rd 2011, 04:38 AM
  2. [SOLVED] Rationalise Denominator
    Posted in the Algebra Forum
    Replies: 8
    Last Post: September 11th 2010, 02:35 PM
  3. rationalise
    Posted in the Math Topics Forum
    Replies: 6
    Last Post: January 15th 2010, 07:57 PM
  4. rationalise
    Posted in the Algebra Forum
    Replies: 2
    Last Post: December 2nd 2009, 11:36 PM
  5. Rationalise the denominator and simplify
    Posted in the Algebra Forum
    Replies: 6
    Last Post: December 26th 2008, 10:32 PM

Search Tags


/mathhelpforum @mathhelpforum