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KCET2012MathematicsVector Algebra

If ( a b )²+( a b )²=144 and | a |=4 , then | b | is equal to

Options

  1. A16
  2. B8
  3. C3
  4. D12

Correct answer

C. 3

Step-by-step solution

Given, ( a b )²+( a b )²=144 (a² b² 1 ² )+a² b² ² =144 a ² ~b ² ( ² + ² )=144 a² b²=144 16 ~b ²=144 ( | a |=4) b ²=9 b =3 or | b |=3

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