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Manipal MET2013MathematicsVector Algebra

If the scalar projection of the vector x i - j + k on the vector 2 i - j +5 k is 1 30 then value of x is equal to

Options

  1. A-5 2
  2. B6
  3. C-6
  4. D3

Correct answer

A. -5 2

Step-by-step solution

Projection of x i - j + k on 2 i - j +5 k = (x i-j+k) (2 i-j+5 k) 4+1+25 = 2 x+1+5 30 But, given, 2 x+6 30 = 1 30 array rrr & 2 x+6=1 & x= -5 2 array

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