Results 1 to 2 of 2

Math Help - [SOLVED] Equation of a Plane

  1. #1
    a_desenhista
    Guest

    [SOLVED] Equation of a Plane

    I was reading a solution and got really confused trying to follow it. Here is what it said.

    Find the equation of a plane passing through e(1,2,3), f(2,5,4) and g(3,4,6)
    A normal to the plane is EF x FG (which I deciphered to mean (F-E) and (G-F)
    since it then said (1,3,1) x (1,-1,2).

    Now the part that really throws me off is here...it then says the answer is (7,-1,-4) therefore the equation is 7x - y - 4z = D. Afterwards they plugged in one of the points into the equation to get D.

    But where did (7,-1,-4) come from?? Help, I'm so lost!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by a_desenhista View Post
    I was reading a solution and got really confused trying to follow it. Here is what it said.

    Find the equation of a plane passing through e(1,2,3), f(2,5,4) and g(3,4,6)
    A normal to the plane is EF x FG (which I deciphered to mean (F-E) and (G-F)
    since it then said (1,3,1) x (1,-1,2).

    Now the part that really throws me off is here...it then says the answer is (7,-1,-4) therefore the equation is 7x - y - 4z = D. Afterwards they plugged in one of the points into the equation to get D.

    But where did (7,-1,-4) come from?? Help, I'm so lost!
    you said the answer yourself. it comes from (1,3,1) x (1,-1,2)

    you do know how to compute the cross-product of vectors, right?

    just evaluate it like a determinant. you want to find:

    \left| \begin{array}{ccc} \bold{i} & \bold{j} & \bold{k} \\ 1 & 3 & 1 \\ 1 & -1 & 2 \end{array}\right| ...that is, the determinant
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 2
    Last Post: May 23rd 2010, 10:46 AM
  2. [SOLVED] Equation to plane through 3 pts
    Posted in the Advanced Algebra Forum
    Replies: 4
    Last Post: March 6th 2010, 05:10 AM
  3. [SOLVED] Scalar equation of a plane
    Posted in the Calculus Forum
    Replies: 1
    Last Post: April 28th 2009, 12:47 PM
  4. [SOLVED] Equation of a plane from 3 vectors
    Posted in the Calculus Forum
    Replies: 3
    Last Post: March 13th 2009, 03:40 PM
  5. [SOLVED] Finding the equation of a plane
    Posted in the Calculus Forum
    Replies: 2
    Last Post: February 6th 2008, 05:29 PM

Search Tags


/mathhelpforum @mathhelpforum