Ex 10.4, 10 - Find area of parallelogram whose adjacent sides are

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


Transcript

Ex 10.4, 10 Find the area of the parallelogram whose adjacent sides are determined by the vectors 𝑎 ⃗ = 𝑖 ̂ − 𝑗 ̂ + 3𝑘 ̂ and b = 2𝑖 ̂ − 7𝑗 ̂ + 𝑘 ̂ . 𝑎 ⃗ = 𝑖 ̂ − 𝑗 ̂ + 3𝑘 ̂ = 1𝑖 ̂ − 1𝑗 ̂ + 3k ̂ 𝑏 ⃗ = 2𝑖 ̂ − 7𝑗 ̂ + 𝑘 ̂ = 2𝑖 ̂ − 7𝑗 ̂ + 1k ̂ Area of parallelogram ABCD = |𝑎 ⃗" × " 𝑏 ⃗ | 𝒂 ⃗ × 𝒃 ⃗ = |■8(𝑖 ̂&𝑗 ̂&𝑘 ̂@1&−1&3@2&−7&1)| = 𝑖 ̂ (−1 × 1 − (−7) × 3) − 𝑗 ̂ (1 × 1 − 2 × 3) + 𝑘 ̂ (1 × −7 − 2 × −1) = 𝑖 ̂ (−1−(−21)) − 𝑗 ̂ (1 − 6) + 𝑘 ̂ (−7 −(−2)) = 𝑖 ̂ (−1 + 21) − 𝑗 ̂ (−5) + 𝑘 ̂ (−7 + 2) = 20 𝒊 ̂ + 5𝒋 ̂ − 5𝒌 ̂ Magnitude of 𝑎 ⃗ × 𝑏 ⃗ = √(202+52+(−5)2) |𝑎 ⃗" × " 𝑏 ⃗ | = √(400+25+25) = √450 = √(25×9×2) = 5 × 3 × √2 = 15 √2 Therefore, the area of parallelogram is 15√𝟐 .

Ask a doubt
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, Social Science, Physics, Chemistry, Computer Science at Teachoo.