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The angle between the vectors a=2 i + j + k and b= i -2 j + k is

Options

  1. A⁻¹ ( 1 6 )
  2. B⁻¹ ( 1 6 )
  3. C⁻¹ ( 1 6 )
  4. D⁻¹ ( 1 6 )

Correct answer

B. ⁻¹ ( 1 6 )

Step-by-step solution

We have, a=2 i + j + k aligned & b= i -2 j + k & |a|= 4+1+1 = 6 & |b|= 1+4+1 = 6 & a b=2 1+1 (-2)+1 1 & a b=2-2+1=1 & = a b |a||b| = 1 6 6 & = ⁻¹ ( 1 6 ) aligned

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