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Three Dimensional Geometry: Direction cosines MCQ

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Direction cosinesEasyQuestion 350001

Question

For direction cosines l, m, n, the relation is:
  1. A
    l² + m² + n² = 1
    Correct
  2. B
    l + m + n = 1
  3. C
    l + m + n = 0
  4. D
    l²+m²+n²=0

Correct answer

l² + m² + n² = 1

Explanation

Direction cosines are the cosines of the angles a line makes with the three coordinate axes. They satisfy l² + m² + n² = 1 always.

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