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📐 Mathematics  ·  Determinants  ·  JEE

The inverse of matrix A = [[1,2],[3,4]] is:

Answer: [[-2,1],[1.5,-0.5]].

  • A [[-2,1],[1.5,-0.5]]
  • B [[4,-2],[-3,1]]
  • C [[1,2],[3,4]]
  • D ||-4,2|,|3,-1||

Correct answer: A. [[-2,1],[1.5,-0.5]]

Explanation: det(A) = 4-6 = -2. adj(A) = [[4,-2],[-3,1]]. A<sup>-1</sup> = (1/-2)[[4,-2],[-3,1]] = [[-2,1],[1.5,-0.5]].

Concept context

Evaluation of determinants, cofactors, adjoint, inverse of matrix, Cramer's rule and area applications. Always in board and JEE.

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