olivia333
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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!
