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The magnitude of projection ofΒ  (2i βˆ’ j + k ) on (i βˆ’ 2j + 2k ) is _______

The magnitude of projection ofΒ  (2i βˆ’ j + k ) on (i βˆ’ 2j + 2k ) is ___

Question 15 (OR 1st Question) - CBSE Class 12 Sample Paper for 2020 Boards - Part 2

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Question 15 (OR 1st Question) The magnitude of projection of (2𝑖 Μ‚ βˆ’ 𝑗 Μ‚ + π‘˜ Μ‚) on (𝑖 Μ‚ βˆ’ 2𝑗 Μ‚ + 2π‘˜ Μ‚) is _______ Projection of vector 𝒂 βƒ— on 𝒃 βƒ— = 𝟏/|𝒃 βƒ— | (𝒂 βƒ—. 𝒃 βƒ—) Let π‘Ž βƒ— = 2𝑖 Μ‚ – 𝑗 Μ‚ + π‘˜ Μ‚ 𝑏 βƒ— = 𝑖 Μ‚ – 2𝑗 Μ‚ + 2π‘˜ Μ‚ (𝒂 βƒ— . 𝒃 βƒ—) = (2 Γ— 1) + (–1 Γ— βˆ’2) + (1 Γ— 2) = 2 + 2 + 2 = 6 Magnitude of 𝑏 βƒ— = √(12+(βˆ’2)2+22) |𝑏 βƒ— | = √(1+4+4) |𝑏 βƒ— | = √9 |𝑏 βƒ— | = 3 Projection of π‘Ž βƒ— on 𝑏 βƒ— = 1/|𝑏 βƒ— | (π‘Ž βƒ—. 𝑏 βƒ—) = 1/3 Γ— 6 = 2 ∴ Magnitude of projection is 2 units

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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.