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# Find u × v, v × u, and v × v. u = (9, 2, 1) v = (−4, 8, −2 )?

### 3 Answers

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- PopeLv 71 month ago
You have been given correct answers for the first two. As for v × v, the cross product of any 3-dimensional vector with itself returns the zero vector.

|v × v| = |v| |v| sin(θ)

The angle θ is the angle between the two argument vectors. Since the vectors are identical, the angle between them is zero, and sin(0) = 0.

- nyphdinmdLv 71 month ago
First note that u x v = - v x u so you only have to do the multiplications once.

u x v = i*(-4 - 8) + j*(-4 - (-18)) + k*(72 - (-8))

= i*(-12) + j*14 + k*80 =(-12, 14,80)

v x u = - u x v = (12, -14, -80)

- rotchmLv 71 month ago
Just plug in your given values and do the cross multiplication.

You do know the procedure, right? It's just following the procedure, following the rules.

If you were not anon I would detail further.

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