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JEE Main2003MathematicsVector AlgebraActual

Let u = i + j , v = i - j and w = i +2 j +3 k . If n is a unit vector such that u n =0 and v n =0 , then | w n | is equal to

Options

  1. A3
  2. B0
  3. C1
  4. D2

Correct answer

A. 3

Step-by-step solution

Since n is perpendicular u and v , n = u v n = | array ccc i & j & k 1 & 1 & 0 1 & -1 & 0 array | 2 2 = -2 k 2 =- k | n |=|( i +2 j +3 k ) (- k )|=|-3|=3

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