Results 1 to 3 of 3
Like Tree1Thanks
  • 1 Post By skeeter

Thread: expansion of equation

  1. #1
    Newbie
    Joined
    Nov 2011
    Posts
    21

    expansion of equation

    Does anybody understand how it goes from (d) to (e)?

    expansion of equation-capture.jpg
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    15,879
    Thanks
    3526

    Re: expansion of equation



    $(-\omega^2m+2k)(-\omega^2 \cdot 3m +k) - (-k)(-k) = 0$

    $(3\omega^4 m^2 - 7\omega^2 mk + 2k^2) - k^2 = 0$

    $(3m^2)\omega^4 - (7mk)\omega^2 + k^2 = 0$

    note the final equation should have $(3m^2)$ as a factor in the first term instead of $(3m)$...
    Last edited by skeeter; Apr 7th 2017 at 01:09 PM.
    Thanks from cxz7410123
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor
    Joined
    Feb 2014
    From
    United States
    Posts
    1,703
    Thanks
    802

    Re: expansion of equation

    $(-\ w^2m + 2k)(-\ w^23m + k) - (-\ k)(-\ k) = -\ mw^2(-\ 3mw^2 + k) + 2k(-\ 3mw^2 + k) - k^2 =$

    $3m^2w^4 - kmw^2 - 6kmw^2 + 2k^2 - k^2 = 3m^2w^4 - 7kmw^2 + k^2.$

    It doesn't.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Navier-Stokes equation component expansion
    Posted in the Calculus Forum
    Replies: 1
    Last Post: Feb 25th 2014, 08:48 AM
  2. Replies: 2
    Last Post: Nov 21st 2013, 12:48 PM
  3. Replies: 3
    Last Post: Oct 6th 2012, 05:29 AM
  4. Replies: 1
    Last Post: Sep 30th 2010, 04:12 AM
  5. expansion and factorisation diophantine equation
    Posted in the Number Theory Forum
    Replies: 1
    Last Post: Feb 17th 2007, 04:53 PM

/mathhelpforum @mathhelpforum