Page 2 of 2 FirstFirst 12
Results 16 to 19 of 19

Math Help - show that mixed partials are equal

  1. #16
    MHF Contributor

    Joined
    Apr 2005
    Posts
    15,725
    Thanks
    1478

    Re: show that mixed partials are equal

    Are you saying that you do not know how to find a derivative of a polynomial? If you are taking a course with questions about partial derivatives, that would be very strange!

    A general polynomial in x and y would be of the form, as Fernando Revilla said, f(x,y)= \sum_{n\ge 0; m\ge 0} a_{mn}x^my^n with only a finite number of a_{mn} non-zero.

    Okay, what is f_x? What is f_y? Now differentiate f_x with respect to y and f_y with respect to x.
    Follow Math Help Forum on Facebook and Google+

  2. #17
    Newbie
    Joined
    Jan 2012
    Posts
    14

    Re: show that mixed partials are equal

    I know how to take derivatives I'm just not use to the notation y'all are using
    Follow Math Help Forum on Facebook and Google+

  3. #18
    MHF Contributor

    Joined
    Apr 2005
    Posts
    15,725
    Thanks
    1478

    Re: show that mixed partials are equal

    It's pretty standard notation:
    f_x= \frac{\partial f}{\partial x}
    f_y= \frac{\partial f}{\partial y}


    The notation D_x and D_y is also used but less commonly.
    Follow Math Help Forum on Facebook and Google+

  4. #19
    Newbie
    Joined
    Jan 2012
    Posts
    14

    Re: show that mixed partials are equal

    I'm not familiar with the summation notation
    Follow Math Help Forum on Facebook and Google+

Page 2 of 2 FirstFirst 12

Similar Math Help Forum Discussions

  1. [SOLVED] Not C^2, but mixed partials exist and are equal.
    Posted in the Calculus Forum
    Replies: 3
    Last Post: December 16th 2011, 07:38 AM
  2. Another "mixed partials" question
    Posted in the Differential Equations Forum
    Replies: 3
    Last Post: September 30th 2011, 05:41 AM
  3. "Mixed partials" question
    Posted in the Differential Equations Forum
    Replies: 1
    Last Post: September 28th 2011, 02:22 AM
  4. Inequality of mixed partials
    Posted in the Calculus Forum
    Replies: 0
    Last Post: January 5th 2010, 10:25 PM
  5. Help me please.... Mixed Partials
    Posted in the Differential Equations Forum
    Replies: 3
    Last Post: September 18th 2009, 08:02 AM

Search Tags


/mathhelpforum @mathhelpforum