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📐 Mathematics  ·  Matrices  ·  JEE

The identity matrix of order 3 has main diagonal elements equal to:

Answer: 1.

  • A 0
  • B 1
  • C 3
  • D Any value

Correct answer: B. 1

Explanation: The identity matrix I has 1s on the main diagonal and 0s everywhere else. It acts like the number 1 in matrix multiplication.

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

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