Can i just find the triple scalar product a.(b x c)

And if it = 0 then it lies in the plane?

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- Jul 22nd 2010, 05:48 AMadam_leedsThree vectors lie in a plane
Can i just find the triple scalar product a.(b x c)

And if it = 0 then it lies in the plane? - Jul 22nd 2010, 06:41 AMPlato
- Jul 22nd 2010, 07:04 AMadam_leeds
- Jul 22nd 2010, 07:29 AMPlato
I don't understand what you are doing.

$\displaystyle v_1\cdot(v_2\times v_3)=72$ - Jul 22nd 2010, 07:45 AMadam_leeds
Yeah i did something wrong, i used this to help me YouTube - The Cross Product :) thanks

- Jul 23rd 2010, 02:49 AMHallsofIvy
A short cut for the triple product is this:

If $\displaystyle v_1= <x_1, y_1, z_1>$, $\displaystyle v_2= <x_2, y_2, z_2>$, and [tex]v_3= <x_3, y_3, z_3> then the cross product is the determinant:

$\displaystyle v_1\cdot(v_2\times v_3)= \left|\begin{array}{ccc}x_1 & y_1 & z_1 \\ x_2 & y_2 & z_2 \\ x_3 & y_3 & z_3 \end{array}\right|$