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COMEDK2016MathematicsVector Algebra

If p = i + j , q =4 k - j and r = i + k , then the unit vector in tile direction of 3 p+q-2 r is

Options

  1. Ai +2 j +2 k
  2. B1 3 ( i -2 j +2 k )
  3. C1 3 ( i -2 j -2 k )
  4. D1 3 ( i +2 j +2 k )

Correct answer

D. 1 3 ( i +2 j +2 k )

Step-by-step solution

We have, p = i + j , q =4 k - j and r = i + k aligned So, 3 p + q -2 i &=3 i +3 j +4 k - j -2 i -2 k &= i +2 j +2 k aligned Now, required unit vector = i +2 j +2 k 1+4+4 = 1 3 ( i +2 j +2 k )

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