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📐 Mathematics  ·  Determinants  ·  JEE

If A is a 3x3 matrix with eigenvalues 1, 2, 3, then trace(A) =

Answer: 5.

  • A 6
  • B 5
  • C 1
  • D 3

Correct answer: B. 5

Explanation: Sum of eigenvalues = trace(A) = 1 + 2 + 3 = 6. Wait: 1+2+3=6, so trace = 6, but option index 1 has value 5 ... correct sum = 6, index = 0 is 6. So correct is index 0.

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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