Results 1 to 2 of 2

Math Help - find the values of a and b given local minimum value and x

  1. #1
    Junior Member
    Joined
    Nov 2012
    From
    fefw
    Posts
    31

    find the values of a and b given local minimum value and x

     f(x) = x^3+ax^2+bx


    local min =  \frac{-2}{9}\sqrt{3}
    x =  \frac{1}{\sqrt{3}}

    The question says if the function  f(x) = x^3+ax^2+bx  has a local min of  \frac{-2}{9}\sqrt{3} at x =  \frac{1}{\sqrt{3}} what are the values of a and b?

    b). which of the tangent lines to the curve in part a has the smallest slope?


    Please lead me in the right way i dont care about the answers just tell me how i would find the values a or b
    i tried plugging in the value of x into f(X) Then i found the derivative and i got stuck
    thanks!!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Sep 2012
    From
    Australia
    Posts
    3,661
    Thanks
    606

    Re: find the values of a and b given local minimum value and x

    Hey mathisfun26.

    Hint: If a function has a minimum at x=a, then f'(a) = 0.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Finding local minimum values
    Posted in the Calculus Forum
    Replies: 1
    Last Post: October 17th 2012, 05:17 PM
  2. Replies: 3
    Last Post: July 25th 2011, 04:31 AM
  3. Replies: 2
    Last Post: December 12th 2010, 12:11 AM
  4. local minimum and maximum values
    Posted in the Calculus Forum
    Replies: 2
    Last Post: August 16th 2010, 03:05 PM
  5. Replies: 0
    Last Post: February 23rd 2010, 09:40 AM

Search Tags


/mathhelpforum @mathhelpforum