Example 1 - If line makes angle 90, 60, 30 with x, y, z-axis - Direction cosines and ratios

  1. Chapter 11 Class 12 Three Dimensional Geometry
  2. Serial order wise
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Example 1 If a line makes angle 90 , 60 and 30 with the positive direction of x, y and z-axis respectively, find its direction cosines. Direction cosines of a line making angle with x- axis, with y- axis and with z axis are l, m, n. l = cos , m = cos , n = cos Here, = 90 , = 60 , = cos 30 So, direction cosines of the line are l = cos 90 , m = cos 60 , n = cos 30 l = 0 , m = 1 2 , n = 3 2 Therefore, direction cosines are 0, ,

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