Question

Given a matrix A=\(\begin{bmatrix}2&3&9\\3&9&6\\1&6&7\end{bmatrix}\), which of the elements aij follows the condition i=j.

(a) 9, 9, 1

(b) 2, 9, 7

(c) 2, 3, 9

(d) 2, 3, 1

I got this question during an interview for a job.

This key question is from Matrices in section Matrices of Mathematics – Class 12

Answer 1

Correct answer is (b) 2, 9, 7

The explanation: The elements following the condition i=j will have the same row number and column number. The elements are a11, a22, a33 which in the matrix A are 2, 3, 9 respectively.