Results 1 to 2 of 2

Math Help - Derivatives about the Tangent Line

  1. #1
    Junior Member
    Joined
    Jan 2009
    From
    vancouver
    Posts
    58

    Unhappy Derivatives about the Tangent Line

    Find an equation of the tangent line to the the graph of the function
    f(x)=(x^(1/2))(3-8x^2)/x

    when x=1.

    Answer: We note that, when x=1, the corresponding point on the graph is given by (1,f(1))=(1,_____), and that the slope of the tangent line
    is f (1)= _____.

    Therefore the equation of the tangent line is y =______
    Last edited by shannon1111; February 13th 2009 at 01:25 PM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Apr 2005
    Posts
    15,393
    Thanks
    1327
    Quote Originally Posted by shannon1111 View Post
    Find an equation of the tangent line to the the graph of the function
    f(x)=(x^(1/2))(3-8x^2)/x

    when x=1.

    Answer: We note that, when x=1, the corresponding point on the graph is given by (1,f(1))=(1,_____), and that the slope of the tangent line
    is f (1)= _____.

    Therefore the equation of the tangent line is y =______
    The first thing I would do is rewrite the function as f(x)(x^(1/2))(3-8x^2)x^(-1)= x^(-1/2)(3-8x^2)= 3x^(-1/2)- 8x^(3/2).

    Surely, you can do the first part: when x= 1, what is f(1)? That's just arithmetic.

    To find the slope, take the derivative of f. Use the fact that the derivative of Ax^n+ Bx^m is nAx^(n-1)+ mBx^(m-1).
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Tangent line derivatives
    Posted in the Calculus Forum
    Replies: 8
    Last Post: October 10th 2010, 08:53 PM
  2. derivatives and line tangent help please
    Posted in the Calculus Forum
    Replies: 1
    Last Post: February 5th 2010, 12:52 AM
  3. Derivatives, slope of tangent line.
    Posted in the Calculus Forum
    Replies: 3
    Last Post: January 26th 2010, 12:35 PM
  4. Derivatives: normal and tangent line
    Posted in the Calculus Forum
    Replies: 1
    Last Post: November 20th 2008, 02:58 PM
  5. Derivatives and tangent line
    Posted in the Calculus Forum
    Replies: 9
    Last Post: October 19th 2008, 09:02 PM

Search Tags


/mathhelpforum @mathhelpforum