Solve the Problem $\frac { 1 } { \sqrt { 6 } } ( \mathbf { i } - 2 \mathbf { j } - 2 \mathbf { k } )$

Multiple Choice

Solve the problem.
-Find a unit vector perpendicular to plane PQR determined by the points P(2, 1, 3) , Q(1, 1, 2) and R(2, 2, 1) .

A) $\frac { 1 } { \sqrt { 6 } } ( \mathbf { i } - 2 \mathbf { j } - 2 \mathbf { k } )$
B) $\frac { 1 } { \sqrt { 6 } } ( \mathbf { i } - 2 \mathbf { j } - \mathbf { k } )$
C) $\frac { 1 } { \sqrt { 6 } } ( \mathbf { i } - 2 \mathrm { j } + \mathbf { k } )$
D) $\frac { 1 } { \sqrt { 6 } } ( - \mathbf { i } - 2 \mathbf { j } - \mathbf { k } )$