Unit vector orthogonal to plane

[olivia333]

Homework Statement

Find a unit vector with positive first coordinate that is orthogonal to the plane through the points P = (-4, 5, 4), Q = (-1, 8, 7), and R = (-1, 8, 8).

Homework Equations

u = PQ = Q - P
v = PR = R - P
ans = uXv = PQ X PR

The Attempt at a Solution

so I did:
PQ = Q - P = (3,3,3)
PR = R - P = (3,3,4)

Then I computed the cross product to get the answer.

|i..j..k|
|3 3 3| = <(12-9) , -(12-9) , (9-9)> = <3, -3, 0>
|3 3 4|

The 0 is correct but the 3 and -3 are not. What am I doing wrong?
Thanks!

 

[tiny-tim]

welcome to pf!

hi olivia! welcome to pf!

The 0 is correct but the 3 and -3 are not. What am I doing wrong?

not a unit vector?

 

[olivia333]

ohhhh haha thank you so much!