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If a → = 3 i ^ - j ^ 10 and b → = i ^ + 3 j ^ + k ^ 11 , then the value of 2 a → + b → ⋅ a → × b → × a → - 3 b → is

Options

  1. A5
  2. B7
  3. C8
  4. D9

Correct answer

B. 7

Step-by-step solution

Given, a → = 3 i ^ - j ^ 10 and b → = i ^ + 3 j ^ + k ^ 11 So, | a → | = 1 ,     | b → | = 1 ,     a → ⋅ b → = 0 2 a → + b → ⋅ a → × b → × a → - 3 b → = 2 a → + b → · a → · a → - 3 b → b → - b → · a → - 3 b → a → = 2 a → + b → · b → + 3 a → = 7

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