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  1. Chapter 10 Class 12 Vector Algebra (Term 2)
  2. Serial order wise

Transcript

Supplementary Exercise Q10 If the vectors 𝐴 βƒ— = a𝑖 Μ‚ + 𝑗 Μ‚ + π‘˜ Μ‚, 𝐡 βƒ— = 𝑖 Μ‚ + b𝑗 Μ‚ + π‘˜ Μ‚ and 𝐢 βƒ— = 𝑖 Μ‚ + 𝑗 Μ‚ + cπ‘˜ Μ‚ are coplanar, then 1/(1βˆ’π‘Ž) + 1/(1βˆ’π‘) + 1/(1βˆ’π‘) = 1, where a, b, c β‰  1 Since Vectors 𝐴 βƒ—, 𝐡 βƒ—, 𝐢 βƒ— are coplanar , ∴ [𝐴 βƒ—" " 𝐡 βƒ—" " 𝐢 βƒ— ] = 0 [𝐴 βƒ—" " 𝐡 βƒ—" " 𝐢 βƒ— ] = |β– 8(π‘Ž&1&1@1&𝑏&1@1&1&𝑐)| 0 = a[(𝑏×𝑐)βˆ’(1Γ—1) ] βˆ’ 1[(1×𝑐)βˆ’(1Γ—1)] + 1[(1Γ—1)βˆ’(1×𝑏) ] 0 = a [π‘π‘βˆ’1]βˆ’[π‘βˆ’1]+1[1βˆ’π‘] 0 = abc – a – c + 1 + 1 – b = 0

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 10 years. He provides courses for Maths and Science at Teachoo.