Zaymiey

📐 Mathematics  ·  Matrices  ·  JEE

The sum of eigenvalues of matrix A = [[3,1],[2,2]] equals:

Answer: 5.

  • A 5
  • B 6
  • C 2
  • D 3

Correct answer: A. 5

Explanation: Sum of eigenvalues = trace(A) = 3 + 2 = 5. Eigenvalues can also be computed: det(lambda*I-A) = (lambda-3)(lambda-2)-2 = lambda<sup>2</sup>-5lambda+4=0. lambda=1,4. Sum=5.

Matrix A (3 rows x 3 columns)a11a12a13a21a22a23a31a32a33column 1column 2column 3row 1row 2row 3

Element aij of matrix A sits at the intersection of row i and column j.

Concept context

Matrix operations, determinants, inverses, and solving linear systems

Read the full Matrices notes →