Ex 10.2, 13 - Chapter 10 Class 12 Vector Algebra

Last updated at April 16, 2024 by

Ex 10.2, 13 - Find direction cosines of A (1, 2, -3), B(-1, -2, 1)

Ex 10.2, 13 - Chapter 10 Class 12 Vector Algebra - Part 2

Go Ad-free

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 ̂ = –2𝑖 ̂ – 4𝑗 ̂ + 4𝑘 ̂ Directions ratios are a = – 2, b = –4, & c = 4 Magnitude of (𝐴𝐵) ⃗ = √((−2)^2+(−4)^2+42) |(𝐴𝐵) ⃗ | = √(4+16+16) = √36 = 6 Directions cosines are (𝑎/|(𝐴𝐵) ⃗ | ,𝑏/|(𝐴𝐵) ⃗ | ,𝑐/|(𝐴𝐵) ⃗ | ) = ((−2)/6,(−4)/6,4/6) = ((−𝟏)/𝟑,(−𝟐)/𝟑,𝟐/𝟑)

Davneet Singh's photo - Co-founder, Teachoo

Made by

Davneet Singh

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 and Computer Science at Teachoo