Results 1 to 3 of 3

Math Help - Parametric and symmetric equations

  1. #1
    Newbie
    Joined
    Feb 2011
    Posts
    2

    Parametric and symmetric equations

    Find symmetric equations for the line through (4, -11, -7)
    that is parallel to the line x = 2+5t, y = −1+ 1
    3 t, z = 9−2t.

    and

    Find parametric equations for the line through (2, -2, 15)
    that is parallel to the xz-plane and the xy-plane.


    I broke the given line down into its original form (r1 plus t x the direction vector). It's clearly the direction vector that the line must be parallel to. I have the r1 vector and the point given in the prompt, but I'm not sure what to do next.

    As for the second one, I figured I would want to take it as the line parallel to the line of intersection of the two planes, which would be the x-axis. Is this the right way to look at it? If so, what then?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,666
    Thanks
    1617
    Awards
    1
    Quote Originally Posted by grejo View Post
    Find symmetric equations for the line through (4, -11, -7) that is parallel to the line x = 2+5t, y = −1+ 13t, z = 9−2t.
    We can see that <5,13,-2> is the direction vector of the line by reading the coefficients of the t's.

    So the symmetric equation we want is \displaystyle\frac{x-4}{5}=\frac{y+11}{13}=\frac{z+7}{-2}.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Feb 2011
    Posts
    2
    Thanks, Plato. That's what I expected with that question, but I kept thinking I needed to do something with the r1 vector. Thanks for the clarifcation.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. How do I do parametric and symmetric equations
    Posted in the Calculus Forum
    Replies: 3
    Last Post: April 21st 2010, 06:36 AM
  2. Replies: 3
    Last Post: March 12th 2009, 04:05 PM
  3. Replies: 2
    Last Post: June 8th 2008, 06:22 AM
  4. Parametric/Symmetric equations
    Posted in the Calculus Forum
    Replies: 1
    Last Post: April 17th 2008, 12:43 AM
  5. Replies: 1
    Last Post: September 1st 2007, 06:35 AM

Search Tags


/mathhelpforum @mathhelpforum