Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Determining the cartesian equations

  1. Jul 25, 2010 #1
    1. The problem statement, all variables and given/known data

    determine the cartesian equation of the plane that contains the following lines:
    L1: r= (4,4,5) + t(5,-4,6)
    L2: r= (4,4,5) + s(2,-3,-4)

    2. Relevant equations

    I kno i'm supposed to use the equation Ax + By + Cz + D. but i don't know how to use it with this type of problem

    3. The attempt at a solution

    Don't understand it at all :S
  2. jcsd
  3. Jul 25, 2010 #2
    Two lines can be contained in a plane if and only if,

    a) The lines are parallel, or
    b) The lines intersect

    Hint: The direction vectors of each line should indicate whether they are parallel or not

    Does that help?
    Last edited: Jul 25, 2010
  4. Jul 25, 2010 #3


    Staff: Mentor

    Ax + By + Cz + D is NOT an equation. The equation you're thinking of is Ax + By + Cz + D = 0.
    You are given a point in the plane and two vectors that are in the plane. You need to work with the two vectors to find a third vector that is perpendicular to the plane.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook