Question:

The number of $3 \times 3$ non-singular matrices with four entries as $1$ and all other entries as $0$ is

Updated On: Aug 1, 2022
  • 6
  • at least 7
  • less than 4
  • 5
Hide Solution
collegedunia
Verified By Collegedunia

The Correct Option is B

Solution and Explanation

The matrix $\begin{pmatrix}1&a&b\\ c&1&d\\ e&f&1\end{pmatrix}$ where exectly one of $a, b,c,d,e,f$ is 1 and rest of them are zero, is invertible. There are six such matrices. Also the matrix $\begin{vmatrix}1&0&1\\ 0&1&0\\ 1&0&0\end{vmatrix}$ is invertible Thus, there are at least 7 such matrices which are invertible.
Was this answer helpful?
0
0

Concepts Used:

Invertible matrices

A matrix for which matrix inversion operation exists, given that it satisfies the requisite conditions is known as an invertible matrix. Any given square matrix A of order n × n is called invertible if and only if there exists, another n × n square matrix B such that, AB = BA = In, where In  is an identity matrix of order n × n.

For example,

It can be observed that the determinant of the following matrices is non-zero.