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COMEDK2024MathematicsVector Algebra

If the vectors a = i +2 j - k , b = i -2 j + k and c = i + j + k are coplanar, then the value of is

Options

  1. A4
  2. B5
  3. C6
  4. D7

Correct answer

D. 7

Step-by-step solution

Given, vector a, b and c are coplanar | array ccc 1 & 2 & -1 1 & -2 & 1 & 1 & 1 array |=0 array r 1(-2- )-2(1- )-1(1+2)=0 -2- -2+2 -3=0 array aligned -7 & =0 & =7 aligned

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