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If A = [3-342-340-11] then A-1 = ______ -

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Question

If A = `[(3, -3, 4), (2, -3, 4), (0, -1, 1)]` then A-1 = ______

Options

  • A

  • A2

  • A3

  • A4

MCQ
Fill in the Blanks

Solution

If A = `[(3, -3, 4), (2, -3, 4), (0, -1, 1)]` then A-1A3

Explanation:

`|A| = |(3, -3, 4), (2, -3, 4), (0, -1, 1)| = 1 ≠ 0`

adj A = `[(1, -1, 0), (-2, 3, -4), (-2, 3, -3)]`

∴ `A^-1 = [(1, -1, 0), (-2, 3, -4), (-2, 3, -3)]`

`A^2 = [(3, -4, 4), (0, -1, 0), (-2, 2, -3)]`

`A^3 = A^2. A = [(1, -1, 0), (-2, 3, -4), (-2, 3, -3)] = A^-1`

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