alleryFor a line with direction cosines l, m, n, the angles it makes with axes are:
AAll equal
Barccos(l), arccos(m), arccos(n) respectively
CRandom
DAlways 60°
Answer & Solution
Correct answer: B. arccos(l), arccos(m), arccos(n) respectively
Direction cosines = cosines of angles.
So α = arccos(l), β = arccos(m), γ = arccos(n).
We have l² + m² + n² = cos²α + cos²β + cos²γ.
So l² + m² + n² = 1.
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