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Let a , b , ( a b ) be unit vectors. What is ( a b ) equal to?

Options

  1. A0
  2. B1 2
  3. C1
  4. D3

Correct answer

A. 0

Step-by-step solution

Given | a | = 1 , | b | = 1 , and | a b | = 1 . Using Lagrange's identity, | a b |^2 + ( a b )^2 = | a |^2 | b |^2 . Substituting the given values, 1^2 + ( a b )^2 = 1^2 1^2 . 1 + ( a b )^2 = 1 . ( a b )^2 = 0 a b = 0 . Answer: 0

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