Target Exam

CUET

Subject

-- Applied Mathematics - Section B2

Chapter

Algebra

Question:

If A and B are any symmetric matrices each of order $3×3$ then $AB - BA$ is :

Options:

a symmetric matrix

a skew-symmetric matrix

a zero matrix

an identity matrix

Correct Answer:

a skew-symmetric matrix

Explanation:

The correct answer is Option (2) → a skew-symmetric matrix

$(AB-BA)^T=(AB)^T-(BA)^T$

$B^TA^T-A^TB^T$

$=BA-AB$ [A and B = Symmetric]

$=-(AB-BA)$

∴ skew-symmetric