Results 1 to 7 of 7

Math Help - Equation of a Tangent to a Curve

  1. #1
    Junior Member
    Joined
    Mar 2009
    Posts
    29

    Equation of a Tangent to a Curve

    Find the points on the curve y = 2 / (3x-2) where the tangent is parallel to the line y = (-3/2)x-1


    Iím not sure I understand what they are asking me to do and how I go about answering this question. Any help is appreciated.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    11,621
    Thanks
    426
    Quote Originally Posted by bearhug View Post
    Find the points on the curve y = 2 / (3x-2) where the tangent is parallel to the line y = (-3/2)x-1


    Iím not sure I understand what they are asking me to do and how I go about answering this question. Any help is appreciated.
    y = \frac{2}{3x-2}

    1. find the derivative of the above function.

    2. set the derivative equal to -\frac{3}{2} ... (why do that ?)

    3. solve for x

    4. determine the point(s), (x,y), on the curve using the x-value(s) found in step 3.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Mar 2009
    Posts
    29
    Because -3/2 is the slope
    Then I find the x-coordinate
    and using the x-coordinate I find the point on the y-coordinate....then I will have my point?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Junior Member
    Joined
    Mar 2009
    Posts
    29
    Is the derivative:

     <br />
y = \frac{-1}{(x-2)^2}<br />
    ??
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    11,621
    Thanks
    426
    familiar with the chain rule?

    y = \frac{2}{3x-2} = 2(3x-2)^{-1}

    y' = -2(3x-2)^{-2} \cdot 3<br />

    y' = -\frac{6}{(3x-2)^2}

    finish.
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Junior Member
    Joined
    Mar 2009
    Posts
    29
    Sorry about that, must be tired from all the math.

    When I sub the slope (-3/2) into the derivative I get -0.14201
    That seems wrong.....is it?
    Follow Math Help Forum on Facebook and Google+

  7. #7
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    11,621
    Thanks
    426
    you do not substitute -\frac{3}{2} in for x ... you set the derivative equal to -\frac{3}{2} and then solve for x, remember?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Equation of tangent to a curve.
    Posted in the Calculus Forum
    Replies: 3
    Last Post: July 12th 2010, 08:23 PM
  2. Equation for line tangent to curve
    Posted in the Calculus Forum
    Replies: 4
    Last Post: September 22nd 2009, 09:29 PM
  3. Equation of the tangent to the curve.
    Posted in the Algebra Forum
    Replies: 2
    Last Post: April 22nd 2009, 07:56 PM
  4. Replies: 1
    Last Post: January 31st 2009, 01:38 PM
  5. equation of the tangent to the curve
    Posted in the Calculus Forum
    Replies: 4
    Last Post: June 17th 2008, 07:51 AM

Search Tags


/mathhelpforum @mathhelpforum