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MHT CET2011MathematicsVector Algebra

If u = a - b and v = a + b and | a |=| b |=2 , then | u v | is equal to

Options

  1. A2 16-(a b)²
  2. B16-( a b )²
  3. C2 4-( a b )²
  4. D2 4+( a b )²

Correct answer

A. 2 16-(a b)²

Step-by-step solution

| u v |=|( a - b ) ( a + b )| =2| a b | ( a a = b b =0) and | a b |²+( a b )²=(a b )²+(a b )² =a² b² array l | a b |= a² b²-( a b )² So, | u v |=2| a b | array array l =2 a² b²-( a b )² =2 2² 2²-( a b )² .=2 16-( a b )² | a |=| b |=2 ) array

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