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COMEDK2012MathematicsVector Algebra

If | a |=2,| b |=7 and a b =3 i +2 j +6 k , then the angle between and b is

Options

  1. A3
  2. B6
  3. C2
  4. D4

Correct answer

B. 6

Step-by-step solution

We have, |a|=2,|b|=7 and x=3 i +2 j +6 M So, |a b|= 9+4+36 = 49 =7 Since, a b |=| a || D | | n 7=(2)(7) 1[ | n |=1] = 1 2 = 6 = 6

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