Results 1 to 2 of 2

Math Help - Question about Tangent lines

  1. #1
    Newbie
    Joined
    Mar 2008
    Posts
    22

    Question about Tangent lines

    Dear All, I am experiencing trouble with a tangent line problem, can anyone give me advice how to approach the problem? Thank you ! 謝謝你

    Question:
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    earboth's Avatar
    Joined
    Jan 2006
    From
    Germany
    Posts
    5,830
    Thanks
    123
    Quote Originally Posted by mak15 View Post
    Dear All, I am experiencing trouble with a tangent line problem, can anyone give me advice how to approach the problem? Thank you ! 謝謝你
    1. Re-write the equation of the function: f(x) = -ax^2+7a

    The graph of this function is a parabola. If a < 0 then the parabola opens down, else it is opening upward.

    2. Calculate the coordinates of the tangent point: T(-1, f(-1))

    3. Determine the first derivative of f and calculate the slope of the tangent line:

    m_t = f'(-1)

    4. Use point-slope-formula to get the equation of the tangent line.

    (I've got: t(x) = y = 2ax + 8a)

    5. Calculate the y-intercept which is t(0).

    6. Calculate the x-intercept which is the solution of the equation t(x) = 0

    7. Calculate the area by:

    A = \int_{-1}^0(t(x)-f(x))dx

    I've got A=\frac13 a
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 3
    Last Post: March 20th 2010, 07:47 PM
  2. Question about tangent lines to circles...
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: February 20th 2010, 01:40 PM
  3. differentiation tangent lines question
    Posted in the Calculus Forum
    Replies: 2
    Last Post: June 6th 2008, 12:38 PM
  4. Quick question regarding tangent lines
    Posted in the Calculus Forum
    Replies: 4
    Last Post: January 5th 2008, 08:42 AM
  5. a question about tangent lines and slopes
    Posted in the Calculus Forum
    Replies: 2
    Last Post: September 14th 2006, 12:29 PM

Search Tags


/mathhelpforum @mathhelpforum