Ex 10.2, 13 - Class 12
Last updated at May 29, 2018 by Teachoo
Transcript
Ex 10.2, 13 Find the direction cosines of the vector joining the points A (1, 2,−3) and B(−1,−2,1), directed from A to B. A( 1, 2 , −3) B(−1, −2, 1) 𝐴𝐵 = (−1 − 1) 𝑖 + (−2 − 2) 𝑗 + (1−(−3)) 𝑘 = –2 𝑖 – 4 𝑗 + 4 𝑘 Directions ratios are a = – 2, b = –4, & c = 4 Magnitude of 𝐴𝐵 = −22+ −42+42 𝐴𝐵 = 4+16+16 = 36 = 6 Directions cosines are 𝑎 𝐴𝐵, 𝑏 𝐴𝐵, 𝑐 𝐴𝐵 = −26, −46, 46 = −𝟏𝟑, −𝟐𝟑, 𝟐𝟑
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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 8 years. He provides courses for Maths and Science at Teachoo. You can check his NCERT Solutions from Class 6 to 12.