Results 1 to 2 of 2

Math Help - Tangent line problem

  1. #1
    Newbie
    Joined
    Feb 2007
    Posts
    9

    Tangent line problem

    Hello, I hope someone can help me with this problem:

    Let   f(x) = x^2 +ax+b for all x. Find values of  a and  b such that the line  y= 2x is tangent to the graph of f at the point (2,4).

    Thanks.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member Matt Westwood's Avatar
    Joined
    Jul 2008
    From
    Reading, UK
    Posts
    824
    Thanks
    33
    Nice one.

    First you need to find out what the gradient of the tangent is. You do that by differentiating the function. Then you look at what values for a and b give you the equation of the line you've been given.

    Need more?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. I need some help with a tangent line problem
    Posted in the Calculus Forum
    Replies: 2
    Last Post: February 22nd 2011, 06:04 PM
  2. Tangent Line Problem
    Posted in the Calculus Forum
    Replies: 1
    Last Post: October 6th 2009, 03:52 PM
  3. Tangent line problem
    Posted in the Calculus Forum
    Replies: 4
    Last Post: February 23rd 2009, 07:38 PM
  4. Need Help With a Tangent Line Problem
    Posted in the Calculus Forum
    Replies: 4
    Last Post: September 30th 2008, 10:34 PM
  5. Tangent Line Problem--Please Help
    Posted in the Calculus Forum
    Replies: 5
    Last Post: November 11th 2007, 02:54 PM

Search Tags


/mathhelpforum @mathhelpforum