Answer: cos(beta) = 2/sqrt(14).
- A cos(beta) = 1/sqrt(14)
- B cos(beta) = 3/sqrt(14)
- C cos(beta) = 1/7
- D cos(beta) = 2/sqrt(14)
Correct answer: D. cos(beta) = 2/sqrt(14)
Explanation: Direction ratios (1,2,3). |d| = sqrt(1+4+9) = sqrt(14). cos(beta) = 2/sqrt(14) (coefficient of y-direction).
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