The angle between two lines whose direction ratios are and is equal to:
Answer and explanation
Correct answer: A.
- Step 1: The cosine of the angle between two vectors and is .
- Step 2: Compute scalar product: .
- Step 3: Since the dot product is identically zero, . The two lines are orthogonal.
Answer
.
Why not the others: uses ; neglects the negative sign; corresponds to .
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