Check sibling questions

Ex 10.4, 1 Class 12 - NCERT Solutions Vector Algebra - Find |a x b|

Ex 10.4, 1 - Chapter 10 Class 12 Vector Algebra - Part 2

This video is only available for Teachoo black users

Introducing your new favourite teacher - Teachoo Black, at only β‚Ή83 per month


Transcript

Ex 10.4, 1 Find |π‘Ž ⃗×𝑏 βƒ— |, if π‘Ž βƒ— = 𝑖 Μ‚ βˆ’ 7𝑗 Μ‚ + 7π‘˜ Μ‚ and 𝑏 βƒ— = 3𝑖 Μ‚ βˆ’ 2𝑗 Μ‚ + 2π‘˜ Μ‚π‘Ž βƒ— = 𝑖 Μ‚ βˆ’ 7𝑗 Μ‚ + 7π‘˜ Μ‚ = 1𝑖 Μ‚ βˆ’ 7𝑗 Μ‚ + 7π‘˜ Μ‚ 𝑏 βƒ— = 3𝑖 Μ‚ βˆ’ 2𝑗 Μ‚ + 2k Μ‚ π‘Ž βƒ— Γ— 𝑏 βƒ— = |β– 8(𝑖 Μ‚&𝑗 Μ‚&π‘˜ Μ‚@β–ˆ(1@3)&β–ˆ(βˆ’7@βˆ’2)&β–ˆ(7@2))| = 𝑖 Μ‚ |β– 8(βˆ’7&7@βˆ’2&2)| βˆ’π‘— Μ‚ |β– 8(1&7@3&2)| + k Μ‚ |β– 8(1&βˆ’7@3&βˆ’2)| = 𝑖 Μ‚ ("βˆ’7 Γ— 2 – (βˆ’2 Γ— 7)" ) βˆ’ 𝑗 Μ‚((1Γ—2 ) βˆ’ (3Γ—7 )) + π‘˜ Μ‚((1Γ—2 ) βˆ’ (3 Γ— βˆ’7)) = 𝑖 Μ‚ (βˆ’14βˆ’(βˆ’14)) βˆ’ 𝑗 Μ‚(2βˆ’21 ) + π‘˜ Μ‚((βˆ’2βˆ’(βˆ’21)) = 𝑖 Μ‚ (0) βˆ’ 𝑗 Μ‚ (βˆ’19) + π‘˜ Μ‚(19) = 0𝑖 Μ‚ + 19𝑗 Μ‚ + 19π‘˜ Μ‚ ∴ 𝒂 βƒ— Γ— 𝒃 βƒ— = 0π’Š Μ‚ + 19𝒋 Μ‚ + 19π’Œ Μ‚ Magnitude of π‘Ž βƒ— Γ— 𝑏 βƒ— = √(02+192+192) |𝒂 βƒ—" Γ—" 𝒃 βƒ— | = √(0+361+361) = √722 = √(19Γ—19Γ—2 ) = 19√𝟐 Therefore, the magnitude of π‘Ž βƒ—" Γ—" 𝑏 βƒ— is 19√𝟐.

Davneet Singh's photo - Teacher, Engineer, Marketer

Made by

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.