Target Exam

CUET

Subject

Maths. Section A

Chapter

Matrices

Question:

Choose the wrong statement.

Options:

For every matrix A, AA' and A'A are square matrices

For every matrix A, AA' is symmetric

For every matrix A, AA' + A'A is defined

For every square matrix A, AA' + A'A is defined

Correct Answer:

For every matrix A, AA' + A'A is defined

Explanation:

The correct answer is Option (3) → For every matrix A, AA' + A'A is defined

Let matrix $A$ be of order $m \times n$.

  • $AA'$ will be of order $m \times m$
  • $A'A$ will be of order $n \times n$

For addition, matrices must have the same order. Since $m \neq n$ in general, $AA' + A'A$ is not always defined.

Hence, Option (3) is incorrect.

  • Option (1): True $\to$ $AA'$ and $A'A$ are always square
  • Option (2): True $\to$ $AA'$ is always symmetric
  • Option (4): True $\to$ If $A$ is square ($n \times n$), both are same order, so addition is defined