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JEE Main202126 Feb 2021Morning ShiftMathematicsVector AlgebraActual

If a → and b → are perpendicular, then a → × a → × a → × a → × b → is equal to:

Options

  1. Aa → 4 b →
  2. B0 →
  3. Ca → × b →
  4. D1 2 a → 4 b →

Correct answer

A. a → 4 b →

Step-by-step solution

a → · b → = 0 a → × a → × b → = a → · b → a → - a → · a → b → = - a → 2 b → Now a → × a → × - a → 2 b → = - a → 2 a → × a → × b → = - a → 2 - a → 2 b → = a → 4 b →

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