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📐 Mathematics  ·  Three Dimensional Geometry  ·  JEE

The direction cosines of a line equally inclined to the three coordinate axes are:

Answer: 1/√3 each.

  • A 1/3 each
  • B 1/√3 each
  • C 1/√2 each
  • D 1 each

Correct answer: B. 1/√3 each

Explanation: Equal cosines l = m = n with l² + m² + n² = 1 give each equal to 1/√3.

zxyOP (x, y, z)

Three mutually perpendicular axes x, y, z meeting at the origin O, with a point P located by its (x, y, z) coordinates.

Concept context

Lines and planes in 3D space, direction cosines, distances, and angles

Read the full Three Dimensional Geometry notes →