Results 1 to 5 of 5

Math Help - Natural Derivative

  1. #1
    Junior Member
    Joined
    Mar 2008
    Posts
    38

    Natural Derivative

    f(x)= ln(5x^4-x)
    Follow Math Help Forum on Facebook and Google+

  2. #2
    -1
    e^(i*pi)'s Avatar
    Joined
    Feb 2009
    From
    West Midlands, England
    Posts
    3,053
    Thanks
    1
    Quote Originally Posted by av8or91 View Post
    f(x)= ln(5x^4-x)
    Use the chain rule

    \frac{d}{dx}ln[f(x)] = \frac{f'(x)}{f(x)}

    In your case f(x)=5x^4-x which s pretty simple to differentiate
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,607
    Thanks
    1574
    Awards
    1
    Quote Originally Posted by av8or91 View Post
    f(x)= ln(5x^4-x)
    The derivative of y=\ln(f(x)) is y'=\frac{f'(x)}{f(x)}.

    So what do you think?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Junior Member
    Joined
    Mar 2008
    Posts
    38
    oh ok I see it now I think. So its just the derivative of the top/ original function on the bottom.

    20x^3-1
    5x^4-x
    Follow Math Help Forum on Facebook and Google+

  5. #5
    -1
    e^(i*pi)'s Avatar
    Joined
    Feb 2009
    From
    West Midlands, England
    Posts
    3,053
    Thanks
    1
    Quote Originally Posted by av8or91 View Post
    oh ok I see it now I think. So its just the derivative of the top/ original function on the bottom.

    20x^3-1
    5x^4-x
    Aside from the syntax then yes

    \frac{20x^3-1}{5x^4-x}
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Derivative of Natural Log
    Posted in the Calculus Forum
    Replies: 3
    Last Post: October 28th 2009, 02:45 PM
  2. derivative involving natural log
    Posted in the Calculus Forum
    Replies: 3
    Last Post: March 9th 2009, 08:54 PM
  3. first derivative with natural log
    Posted in the Calculus Forum
    Replies: 9
    Last Post: October 9th 2008, 03:43 PM
  4. Derivative of a Natural Log
    Posted in the Calculus Forum
    Replies: 11
    Last Post: April 20th 2008, 12:52 PM
  5. Derivative of Natural Log
    Posted in the Calculus Forum
    Replies: 16
    Last Post: March 15th 2007, 06:24 PM

Search Tags


/mathhelpforum @mathhelpforum