Given 3D vectors and , what is the cosine of the angle between them?
Answer and explanation
Correct answer: C.
- Step 1: Compute dot product: .
- Step 2: Compute magnitudes: and .
- Step 3: Apply formula: .
Answer
-4/9.
Why not the others: '' has incorrect sign; '' divides by single magnitude; '' assumes orthogonal vectors.
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