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MHT CET202122 Sep 2021Morning ShiftMathematicsVector AlgebraActual

If a , b , c are mutually perpendicular vectors having magnitudes 1,2,3 respectively, then [ a + b + c b - a c ]=

Options

  1. A12
  2. B18
  3. C0
  4. D6

Correct answer

A. 12

Step-by-step solution

aligned & [ a + b + c b - a c ] & =( a + b + c ) [( b - a ) c ] & =( a + b + c ) [( b c )-( a c )] & = a ( b c )- b ( a c )= a ( b c )+ b ( c a ) & =2 a ( b c )=2(1)(2)(3)=12 aligned

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