Results 1 to 2 of 2

Math Help - coordinate geometry

  1. #1
    Newbie
    Joined
    Mar 2008
    Posts
    9

    Exclamation coordinate geometry

    1)find in terms of t,the equation of the line through the point (t,0) with gradient t.

    2)find the equation of the line with gradient \frac {1}{t},(t does not equal to 0)which passes through the point ( t^2,2t).I fthis line passes through the point (-2,1) find the possible values of t.
    Last edited by tyana21; March 30th 2008 at 01:02 AM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member Danshader's Avatar
    Joined
    Mar 2008
    From
    http://en.wikipedia.org/wiki/Malaysia now stop asking me where is malaysia...
    Posts
    158
    1) well from the linear line general equation of y= mx +c, where m is your gradient and c is your y-intercept;

    substituting the coordinates of the point (t,0) → x-coordinate = t, y-coordinate = 0 and also substituting the gradient into the general equation we get:

    0 = t(t) + c
    c = t^2

    therefore the equation for the line with gradient t and passing through the point (t,0) is

    y = tx + t^2



    2)
    using the same method above with gradient now 1/t, x-coordinate = t^2 and y-coordinate = 2t,

    2t = (1/t)(t^2) + c
    c = t

    therefore the equation of the line is:

    y = (1/t)x + t


    when the line passes through (-2,1) we substitute x-coordinate = -2 and y-coordinate = 1 into the equation to get:

    1 = (1/t)(-2) + t
    t = -2 + t^2
    t^2 - 2 - t = 0
    (t +2)(t-1) = 0
    t=-2,1
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Coordinate Geometry
    Posted in the Geometry Forum
    Replies: 1
    Last Post: February 16th 2011, 12:06 AM
  2. Coordinate Geometry
    Posted in the Geometry Forum
    Replies: 1
    Last Post: June 5th 2010, 05:21 AM
  3. coordinate geometry
    Posted in the Algebra Forum
    Replies: 6
    Last Post: November 25th 2009, 08:28 AM
  4. coordinate geometry
    Posted in the Pre-Calculus Forum
    Replies: 3
    Last Post: November 24th 2009, 10:35 AM
  5. Coordinate Geometry
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: September 12th 2008, 05:26 PM

Search Tags


/mathhelpforum @mathhelpforum