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  1. Chapter 10 Class 12 Vector Algebra
  2. Serial order wise
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Example 26 (Supplementary NCERT) Find π‘ŽΒ βƒ—.(𝑏 ⃗ Γ— 𝑐 ⃗), if π‘ŽΒ βƒ— = 2𝑖 ̂ + 𝑗 ̂ + 3π‘˜Β Μ‚ , 𝑏 ⃗ = –𝑖 ̂ + 2𝑗 ̂ + π‘˜Β Μ‚ , 𝑐 ⃗ = 3𝑖 ̂ + 𝑗 ̂ + 2π‘˜Β Μ‚Given, π‘ŽΒ βƒ— = 2𝑖 ̂ + 𝑗 ̂ + 3π‘˜Β Μ‚ , 𝑏 ⃗ = –𝑖 ̂ + 2𝑗 ̂ + π‘˜Β Μ‚ , 𝑐 ⃗ = 3𝑖 ̂ + 𝑗 ̂ + 2π‘˜Β Μ‚ π‘ŽΒ βƒ—.(𝑏 ⃗ Γ— 𝑐 ⃗) = [π‘ŽΒ βƒ—" " 𝑏 ⃗" " 𝑐 ⃗ ] = |β– 8(2&1&3@βˆ’1&2&1@3&1&2)| = 2[(2Γ—2)βˆ’(1Γ—1) ] βˆ’ 1[(βˆ’1Γ—2)βˆ’(3Γ—1) ] + 3[(βˆ’1Γ—1)βˆ’(3Γ—2)] = 2 [4βˆ’1]βˆ’1(βˆ’2βˆ’3)+3[βˆ’1βˆ’6] = 2(3) – 1(–5) + 3(–7) = 6 + 5 – 21 = 11 – 21 = – 19 ∴ π‘ŽΒ βƒ—.(𝑏 ⃗ Γ— 𝑐 ⃗) = –19

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