Results 1 to 7 of 7

Math Help - Finding the gradient function.... lost

  1. #1
    Member
    Joined
    Apr 2009
    Posts
    136
    Awards
    1

    Finding the gradient function.... lost

    Hi all,

    Firstly I am asked to differentiate y= x^4 - 3x^2 + 6

    I get 4x^3 - 6x I am sure this correct, please advise if not

    I am lost with the gradient function of this one

    y = 3/x^2 - 2x + 5

    not sure what to do with the initial fraction

    thinking it should be

    ????? - 2 ??

    Cheers
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,395
    Thanks
    1481
    Awards
    1
    Quote Originally Posted by Joel View Post
    the gradient function of this one
    y = 3/x^2 - 2x + 5
    If y=\frac{c}{f(x)} then y'=\frac{-cf'(x)}{(f(x))^2}
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Apr 2009
    Posts
    136
    Awards
    1
    If then

    Therefore

    y = 3/x^2 - 2x + 5

    dy/dx -3 (2x) / (x^2)^2 -2

    -6x/x^4 -2 ????

    Is this correct?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by Joel View Post
    Hi all,

    Firstly I am asked to differentiate y= x^4 - 3x^2 + 6

    I get 4x^3 - 6x I am sure this correct, please advise if not

    I am lost with the gradient function of this one

    y = 3/x^2 - 2x + 5

    not sure what to do with the initial fraction

    thinking it should be

    ????? - 2 ??

    Cheers
    You need to be less ambiguous. Is it y = \frac{3}{x^2} - 2x + 5 or y = \frac{3}{x^2 - 2x + 5}?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Member
    Joined
    Apr 2009
    Posts
    136
    Awards
    1
    Follow Math Help Forum on Facebook and Google+

  6. #6
    MHF Contributor

    Joined
    Apr 2005
    Posts
    14,977
    Thanks
    1121
    Quote Originally Posted by Joel View Post
    Then y= 3x^{-2}- 2x+ 5. That's easier than using the quotient rule.
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Member
    Joined
    Apr 2009
    Posts
    136
    Awards
    1
    .

    this would make

    y'' = -6xˉ - 2 ??
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Finding The Gradient Of A Matrix Equation
    Posted in the Calculus Forum
    Replies: 12
    Last Post: May 9th 2011, 07:57 PM
  2. Finding the gradient
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: December 14th 2009, 05:53 PM
  3. Finding Gradient
    Posted in the Algebra Forum
    Replies: 1
    Last Post: October 14th 2009, 01:54 AM
  4. Replies: 6
    Last Post: September 14th 2009, 06:19 PM
  5. [SOLVED] finding the gradient vector
    Posted in the Calculus Forum
    Replies: 4
    Last Post: May 27th 2009, 08:15 PM

Search Tags


/mathhelpforum @mathhelpforum