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JEE Main2010MathematicsVector AlgebraActual

Let a = j - k and c = i - j - k . Then vector b satisfying a b + c = 0 and a b =3 is

Options

  1. A2 i - j +2 k
  2. Bi - j -2 k
  3. Ci + j -2 k
  4. D- i + j -2 k

Correct answer

D. - i + j -2 k

Step-by-step solution

c = b a b c =0 ( b ₁ i + b ₂ j + b ₃ k ) ( i - j - k )=0 ~b ₁- b ₂- b ₃=0 and a b =3 b ₂- b ₃=3 ~b ₁= b ₂+ b ₃=3+2 ~b ₃ b = (3+2 ~b ₃ ) i + (3+ b ₃ ) j + b ₃ k

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