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MHT CET2019Evening ShiftMathematicsMatricesActual

If 1 + 2 i i - i 1 - 2 i where i = - 1 , then A (adj A) = ….

Options

  1. A-2 l
  2. B2 l
  3. C5 l
  4. D4 l

Correct answer

D. 4 l

Step-by-step solution

A = 1 + 2 i i - i 1 - 2 i ∴ A = 1 + 2 i i - i 1 - 2 i = 1 + 2 i 1 - 2 i + i 2 = 1 - 2 i 2 + - 1 = 1 + 4 - 1 = 4 ∴ A a d j A = A = 4

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