Question 4 (OR 2 nd question)

Find the direction cosines of the line:

  (x - 1)/2 = –y = (z + 1)/2

Find the direction cosines of line: (x – 1)/2 = – y = (z + 1)/2

Question 4 (Or 2nd) - CBSE Class 12 Sample Paper for 2019 Boards - Part 2

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Transcript

Question 4 (OR 2nd question) Find the direction cosines of the line: (𝑥 − 1)/2 = –y = (𝑧 + 1)/2 Given line (𝑥 − 1)/2 = –y = (𝑧 + 1)/2 (𝑥 − 1)/2 = (−𝑦)/1 = (𝑧 + 1)/2 (𝑥 − 1)/2 = 𝑦/(−1) = (𝑧 + 1)/2 So, direction ratios are 2, –1, 2 ∴ a = 2, b = –1, c = 2 Direction cosines = 2/√(2^2 + (−1)^2 + 2^2 ) ,(−1)/√(2^2 + (−1)^2 + 2^2 ) ,2/√(2^2 + (−1)^2 + 2^2 ) = 2/√(4 + 1 + 4) ,(−1)/√(4 + 1 + 4) ,2/√(4 + 1 + 4) = 2/√9 ,(−1)/√9 ,2/√9 = 𝟐/𝟑 ,(−𝟏)/𝟑 ,𝟐/𝟑

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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.