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📐 Mathematics  ·  Determinants  ·  JEE

The characteristic polynomial of [[2,1],[0,3]] is:

Answer: (lambda-2)(lambda-3).

  • A (lambda-2)(lambda-3)
  • B lambda<sup>2</sup>+5lambda+6
  • C lambda<sup>2</sup>-5lambda-6
  • D 2lambda<sup>2</sup>-3

Correct answer: A. (lambda-2)(lambda-3)

Explanation: Characteristic polynomial: det(λI − A) = det[[λ−2, −1],[0, λ−3]] = (λ−2)(λ−3) − 0 = (λ−2)(λ−3). This is an upper triangular matrix, so eigenvalues are the diagonal entries 2 and 3. Answer: (λ−2)(λ−3).

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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