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: Triple Integrals Over General Regions

  1. Feb 26, 2004 #1

    First I will post my question:

    It has been quite a while since my last calculus course so I don't remember everything. Now here is MY question: How do I find the equation of the plane in which the region E lies below?

    I know from the solution manual that the E is the region that lies below the plane

    2z + 6x + 3y = 6

    How do I find that out?

    I found three separate equations for each plane - xy, yz, xz.

    6 = 2z + 6x, 6 = 2z + 3x, 6 = 3y + 6x.

    And I can see the relationship between all four planes. How do I come up with the final equation of the plane

    2z + 6x + 3y = 6

    I should know this. I just can't remember.

    Any help is appreciated. Thankyou.
  2. jcsd
  3. Feb 26, 2004 #2
    Define two vectors between points A(1,0,0), B(0,2,0), and C(0,0,3). It doesn't matter which pair of points you use to make the vectors, as long as the vectors are different.

    The cross product of these two vectors will be normal to the plane. Then the equation,
    [tex]n_x(x-x_0) + n_y(y-y_0) + n_z(z-z_0)=0[/tex]
    will describe the plane.


  4. Feb 26, 2004 #3
    Thanks for the help cookie monster.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook