Results 1 to 3 of 3

Math Help - how to graph function

  1. #1
    Senior Member euclid2's Avatar
    Joined
    May 2008
    From
    Ottawa, Canada
    Posts
    400
    Awards
    1

    how to graph function

    a function has a local maximum at x=-2, a local maximum at x=6, and a local minimum at x=1. what does this information tell you about the function? how do i graph this? of what degree would this function be? i started by marking of course x=-2,x=6,x=1 on the graph but unsure of what to do now.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Prove It's Avatar
    Joined
    Aug 2008
    Posts
    11,344
    Thanks
    1247
    I don't think you've got enough information. From what you've been given, your function must be at least a quartic. This means its derivative is at least a cubic and its second derivative is at least a quadratic.

    You are told that there is a local maximum at x = -2. So f'(-2) = 0 and f''(-2) < 0.

    You are told that there is a local maximum at x = 6. So f'(6) = 0 and f''(6) < 0.

    You are told that there is a local minimum at x = 1. So f'(1) = 0 and f''(1) > 0.


    Since f'(-2) = f'(6) = f'(1) = 0, that means

    f'(x) = a(x - 6)(x - 1)(x + 2).


    You could expand this, then integrate to find a family of curves for f(x), but unless you are given some points that lie on the curve, you won't be able to evaluate the exact curve.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Senior Member euclid2's Avatar
    Joined
    May 2008
    From
    Ottawa, Canada
    Posts
    400
    Awards
    1
    so even something like this would work? Imageshack - graphgr.png - Uploaded by nameme

    please excuse the ridiculous graph i'm sure you get the idea
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. How do I graph this sin function?
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: May 21st 2011, 06:25 PM
  2. graph function
    Posted in the Pre-Calculus Forum
    Replies: 10
    Last Post: October 17th 2010, 10:19 PM
  3. function name on graph
    Posted in the Math Software Forum
    Replies: 7
    Last Post: May 31st 2010, 08:29 PM
  4. Replies: 2
    Last Post: August 26th 2009, 04:51 AM
  5. Graph of Function F/F'
    Posted in the Calculus Forum
    Replies: 2
    Last Post: October 10th 2007, 05:09 PM

Search Tags


/mathhelpforum @mathhelpforum