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KCET2009MathematicsVector Algebra

If a +2 b +3 c = 0 , then a b + b c + c a is equal to

Options

  1. A2( b c )
  2. B3( c a )
  3. C0
  4. D6( b c )

Correct answer

D. 6( b c )

Step-by-step solution

Given, a +2 b +3 c = 0 ...(i) Taking cross product with b , we get a b +2 b b +3 c b = 0 b a b =3 b c Again taking cross product with c of Eq. (i), we get a c +2 b c +3 c c = 0 c c a =2 b c a b + b c + c a =3 b c + b c +2 b c =6( b c )

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