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lf a line makes angles α, β, γ with OX, OY, OZ respectively where O = (0, 0, 0), then cos2α + cos2β + cos2γ is

lf a line makes angles α, β, γ with OX, OY, OZ respectively where O = (0, 0, 0), then cos2α + cos2β + cos2γ is Correct Answer -1

Concept:

  1. Direction angles: If α, β, and γ are the angles made by the line segment with the coordinate axis then these angles are termed to be the direction angles.
  2. Direction cosines: The cosines of direction angles are the direction cosines of the line. Hence, cos α, cos β and cos γ are called as the direction cosines

It is denoted by l, m and n. ⇔ l = cos α, m = cos β and n = cos γ

– 3

= 2 × 1 – 3

= -1

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