Miscellaneous

Chapter 11 Class 12 Three Dimensional Geometry
Serial order wise

Transcript

Misc 2 (Introduction) Find the equation of a line parallel to x-axis and passing through the origin.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 makes an angle 0° with x – axis, 90° with y – axis & 90° with z – axis. So, 𝜶 = 0°, 𝜷 = 90°, 𝜸 = 90° Direction cosines are l = cos 0° , m = cos 90° , n = cos 90° l = 1 , m = 0, n = 0 ∴ Direction cosines of x – axis are 1, 0, 0. Misc 2 Find the equation of a line parallel to x-axis and passing through the origin.Equation of a line passing through (x1, y1, z1) and parallel to a line with direction ratios a, b, c is (𝒙 − 𝒙𝟏)/𝒂 = (𝒚 − 𝒚𝟏)/𝒃 = (𝒛 − 𝒛𝟏)/𝒄 Since line passes through origin ie. (0, 0, 0), x1 = 0, y1 = 0, z1 = 0 Since line is parallel to x – axis, 𝒂 = 1, b = 0, c = 0 Equation of line is (𝑥 − 0)/1 = (𝑦 − 0)/0 = (𝑧 − 0)/0 𝒙/𝟏 = 𝒚/𝟎 = 𝒛/𝟎

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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 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.