Target Exam

CUET

Subject

-- Applied Mathematics - Section B2

Chapter

Algebra

Question:

Which of the following is NOT correct?

Options:

If matrix B is the inverse of matrix A, then A is the inverse of B.

A rectangular matrix of order $m×n,m≠n$ does not possess an inverse.

If A and B are symmetric matrices of the same order, then (AB-BA) is a skew-symmetric matrix.

If a square matrix is invertible, then it may have more than one inverse.

Correct Answer:

If a square matrix is invertible, then it may have more than one inverse.

Explanation:

The correct answer is Option (4) → If a square matrix is invertible, then it may have more than one inverse.

Check each statement.

If $B=A^{-1}$ then $A=B^{-1}$, so the first statement is correct.

A non-square matrix cannot have an inverse, so the second statement is correct.

If $A$ and $B$ are symmetric, then $(AB-BA)^{T}=B^{T}A^{T}-A^{T}B^{T}=BA-AB=-(AB-BA)$, so it is skew-symmetric. Hence the third statement is correct.

An invertible square matrix has a unique inverse, so the statement saying it may have more than one inverse is false.

final answer: If a square matrix is invertible, then it may have more than one inverse.