Find Vector Perpendicular to Plane

[brinlin]

Find a vector that is perpendicular to the plane passing through the points P (1, 2, 3), Q (2, 3, 1), and R (3, 1, 2).

 

[skeeter]

vector product yields a vector perpendicular to two vectors ...

$\vec{PQ} \times \vec{PR}$

 

[brinlin]

I'm sorry I don't really understand.

 

[skeeter]

I'm sorry I don't really understand.

you don't understand, or you don't know what a vector product is and how to calculate it?

$\vec{PQ} = (1,1,-2)$
$\vec{PR} = (2,-1,-1)$

$ \vec{PQ} \times \vec{PR} = \begin{vmatrix} \hat{i} & \hat{j} & \hat{k} \\ 1& 1 & -2 \\ 2 &-1 &-1 \\ \end{vmatrix} $