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 𝛼 with x- axis, 𝛽 with y- axis and 𝛾 with z – axis are l, m, n. l = cos 𝜶, m = cos 𝜷 , n = cos 𝜸 Here, 𝛼 = 90° , 𝛽 = 60° , 𝛾 = 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, 𝟏/𝟐, √𝟑/𝟐

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.

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