Zaymiey

📐 Mathematics  ·  Three Dimensional Geometry  ·  JEE

The image of the origin in the plane 2x-y+2z=9 is:

Answer: (4,-2,4).

  • A (2,-1,2)
  • B (4/3,-2/3,4/3)
  • C (4,-2,4)
  • D (1,-1/2,1)

Correct answer: C. (4,-2,4)

Explanation: The foot of perpendicular from origin: normal direction (2,-1,2). Point on normal: (2t,-t,2t). On plane: 4t+t+4t=9t=9, t=1. Foot=(2,-1,2). Image = 2*foot - origin = (4,-2,4).

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

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