Results 1 to 3 of 3

Math Help - finding eq. of tan to the slope f(x) given the slope

  1. #1
    Newbie
    Joined
    Sep 2009
    Posts
    15

    finding eq. of tan to the slope f(x) given the slope

    I know how to do this problem but I just totally had a brain fade and cant seem to figure it out, can someone lead me into the right direction here?

    Last edited by mr fantastic; December 8th 2009 at 12:54 PM. Reason: rt --> de
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member DeMath's Avatar
    Joined
    Nov 2008
    From
    Moscow
    Posts
    473
    Thanks
    5
    Quote Originally Posted by tecknics View Post
    I know how to do this problem but I just totally had a brain fade and cant seem to figure it out, can someone lead me into the right direction here?

    y = \sqrt {x + 9}.

    An equation of the tangent
    \boxed{y = {{y'}_0}\left( {x - {x_0}} \right) + {y_0}}

    By the condition of your task, you have

    {{y'}_0} = {\left( {\sqrt {{x_0} + 9} } \right)^\prime } = \frac{1}<br />
{4} \, \Rightarrow \, \frac{1}{{2\sqrt {{x_0} + 9} }} = \frac{1}{4} \Leftrightarrow \sqrt {{x_0} + 9}  = 2 \Rightarrow {x_0} =  - 5.

    {y_0} = \sqrt { - 5 + 9}  = \sqrt 4  = 2.

    Finally, you get this equation of the tangent

    y = \frac{1}{4}\left( {x + 5} \right) + 2 = \frac{x}{4} + \frac{{13}}{4}.

    See this picture

    Last edited by mr fantastic; December 8th 2009 at 12:54 PM.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Sep 2009
    Posts
    15
    Perfect! Thank you!
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 6
    Last Post: September 11th 2011, 05:53 PM
  2. Finding Coordinates of a Slope
    Posted in the Geometry Forum
    Replies: 2
    Last Post: May 28th 2010, 07:09 AM
  3. finding slope
    Posted in the Algebra Forum
    Replies: 4
    Last Post: March 29th 2010, 03:48 AM
  4. Finding the slope of the tangent
    Posted in the Calculus Forum
    Replies: 5
    Last Post: March 22nd 2010, 04:18 PM
  5. Finding slope
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: April 4th 2007, 03:58 PM

Search Tags


/mathhelpforum @mathhelpforum