Example 11 - Chapter 10 Class 12 Vector Algebra - Part 3


Transcript

Example 11 Consider two points P and Q with position vectors (𝑂𝑃) ⃗ = 3𝑎 ⃗ − 2𝑏 ⃗ and (𝑂𝑄) ⃗ = 𝑎 ⃗ + 𝑏 ⃗ . Find the position vector of a point R which divides the line joining P and Q in the ratio 2 : 1, (ii) externally. Position vector of R = (2(𝑂𝑄) ⃗ − 1(𝑂𝑃) ⃗)/(𝟐 − 𝟏) (𝑂𝑅) ⃗ = (2(𝑎 ⃗ + 𝑏 ⃗ ) − 1(3𝑎 ⃗ − 2𝑏 ⃗))/(2 − 1) = (2𝑎 ⃗ + 2𝑏 ⃗ − 3𝑎 ⃗ + 2𝑏 ⃗)/1 = −𝑎 ⃗ + 4𝑏 ⃗ = 4𝒃 ⃗ − 𝒂 ⃗

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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.