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MHT CET202120 Sep 2021Morning ShiftMathematicsVector AlgebraActual

If e ₁, e ₂ and e ₁+ e ₂ are unit vectors, then the angle between e ₁ and e ₂ is

Options

  1. A150^
  2. B120^
  3. C90^
  4. D135^

Correct answer

B. 120^

Step-by-step solution

aligned & | e ₁+ e ₂ |^2= | e ₁^2 |+ | e ₂^2 |+2 e ₁ e ₂ & Here | e ₁ |=1, | e ₂ |=1 and | e ₁+ e ₂ |=1 & (1)=(2)^2+(1)^2+2(1)(1) & -1 2 = =120^ aligned

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