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JEE Main202430 Jan 2024Evening ShiftMathematicsVector AlgebraActual

Let a → and b → be two vectors such that | b → | = 1 and | b → × a → | = 2 Then | ( b → × a → ) - b → | 2 is equal to

Options

  1. A3
  2. B5
  3. C1
  4. D4

Correct answer

B. 5

Step-by-step solution

Given: b → = 1 , b → × a → = 2 Now, solving b → × a → - b → 2 , ⇒ b → × a → - b → 2 = b → × a → 2 + b → 2 - 2 b → × a → · b → Now, we know that, b → × a → · b → = b → × a → · a → = 0 ⇒ b → × a → - b → 2 = 2 2 + 1 2 - 2 × 0 ⇒ b → × a → - b → 2 = 5

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