Results 1 to 2 of 2

Math Help - calculus

  1. #1
    Newbie
    Joined
    Nov 2008
    Posts
    3

    calculus

    Determine the parametric equations for the line that passes through the two points A=(4, -1, 5) and B= (3, 5, -1).
    At what point does this line intersect the x-y plane


    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member bkarpuz's Avatar
    Joined
    Sep 2008
    From
    R
    Posts
    481
    Thanks
    2
    Quote Originally Posted by tob2dam View Post
    Determine the parametric equations for the line that passes through the two points A=(4, -1, 5) and B= (3, 5, -1).
    At what point does this line intersect the x-y plane

    As you know a line equation in \mathrm{R}^{3} has the following form:
    \alpha(t):=A+tu,\qquad t\in\mathbb{R},
    where A is a point that line passes through, and u\neq(0,0,0) is a vector that is parallel to the line.
    Returning to your problem, we have a point that the desired line passes through (we may pick (4, -1, 5) or (3, 5, -1)), but we need the vector u.
    We may let u as AB vector, try to see that the line will be parallel to AB=B-A=(-1,6,-6).
    Thus, the line is
    \alpha(t):=(4,-1,5)+t(-1,6,-6),\qquad t\in\mathbb{R}.
    To find the value that line intersects xy-plane, we have to set the third component (height) of the line to 0 and solve t.
    I hope you can find it now?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 1
    Last Post: December 13th 2011, 09:11 PM
  2. Replies: 2
    Last Post: June 25th 2010, 10:41 PM
  3. Replies: 1
    Last Post: February 11th 2010, 07:09 AM
  4. Calculus III But doesn't require Calculus :)
    Posted in the Calculus Forum
    Replies: 1
    Last Post: June 19th 2009, 04:23 PM
  5. Replies: 1
    Last Post: June 23rd 2008, 09:17 AM

Search Tags


/mathhelpforum @mathhelpforum