1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Cartesian equation of a plane

  1. Oct 14, 2008 #1
    this is just a simple question

    For a plane in vector form, can the cartesian equation (Ax+By+Cz+D=0) be found by finding the cross product of the two vectors? My understanding is that A, B and C are the components of the normal of the plane, which can be found by doing the cross product. However, upon comparing my answers to those of a classmate, I discovered our answers were different, he used a method of substitution/elimination.
     
  2. jcsd
  3. Oct 14, 2008 #2

    Defennder

    User Avatar
    Homework Helper

    Getting the normal to the plane isn't enough since any vector is normal to an infinite number of parallel planes. You must take the dot product of the plane normal vector with the position vector from a reference point on the plane to an arbitrary point on the plane (x,y,z) to get the equation. Your two answers should be the same, except that his may differ from yours by a multiple of the plane equation.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?