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प्रश्न
If a line makes angle 90°, 60° and 30° with the positive direction of X, Y and Z axes respectively, find its direction cosines
उत्तर
Let the direction cosines of the line be l, m, n.
∴ l = cos 90°, m = cos 60°, n = cos 30°
∴ l = 0, m = `1/2`, n = `sqrt(3)/2`
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