Results 1 to 2 of 2

Math Help - derivative problem

  1. #1
    Newbie
    Joined
    Nov 2011
    Posts
    6

    derivative problem

    find derivative of square root of -x minus x. (x<0).

    the books answer is -1/2-x^1/2-1. how do they keep the negative under the square root sign?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor MarkFL's Avatar
    Joined
    Dec 2011
    From
    St. Augustine, FL.
    Posts
    1,988
    Thanks
    734

    Re: derivative problem

    You might want to write the function as:

    f(x)=(-x)^{\frac{1}{2}}-x

    Now differentiate term by term, using the power and chain rules on the first term. The convert back to radical notation. You will then see why the negative stays with the x under the radical.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Another derivative problem
    Posted in the Calculus Forum
    Replies: 4
    Last Post: May 3rd 2012, 04:03 PM
  2. derivative problem
    Posted in the Calculus Forum
    Replies: 6
    Last Post: March 9th 2010, 05:47 AM
  3. derivative problem
    Posted in the Calculus Forum
    Replies: 0
    Last Post: March 2nd 2010, 04:21 PM
  4. derivative problem with ln
    Posted in the Calculus Forum
    Replies: 3
    Last Post: October 19th 2009, 04:59 PM
  5. Derivative problem
    Posted in the Calculus Forum
    Replies: 2
    Last Post: August 14th 2009, 06:02 AM

Search Tags


/mathhelpforum @mathhelpforum