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Learn in your speed, with individual attention - Teachoo Maths 1-on-1 Class


Transcript

Example 4 Find the direction cosines of x, y and z-axis.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 x – axis x – axis makes an angle 0° with x – axis, 90° with y – axis & 90° with z – axis. So, 𝛼 = 0°, 𝛽 = 90°, 𝛾 = 90° l = cos 90°, m = cos 0°, n = cos 90° l = 0, m = 1, n = 0 ∴ Direction cosines of x – axis are 1, 0, 0 y – axis y – axis makes an angle 90° with x – axis, 0° with y – axis & 90° with z – axis. So, 𝛼 = 90°, 𝛽 = 0°, 𝛾 = 90° Direction cosines are l = cos 90°, m = cos 0° , n = cos 90° l = 0, m = 1, n = 0 ∴ Direction cosines of y – axis are 0, 1, 0 z – axis z – axis makes an angle 90° with x – axis, 90° with y – axis & 0° with z – axis. So, 𝛼 = 90°, 𝛽 = 90°, 𝛾 = 0° Direction cosines are l = cos 90°, m = cos 90°, n = cos 0° l = 0, m = 0, n = 1 ∴ Direction cosines of z – axis are 0, 0, 1.

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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.