Question

Let $A$ and $B$ are two square matrices such that the trace of $AB=30,$ then the trace of $BA$ is equal to

• A. $\frac{1}{30}$
• B. $30$
• C. $-30$
• D. Cannot be determined

Answer 1

The correct option is B $30$

For two square matrices $A$ and $B$
Trace of $AB=$ Trace of $BA$
$\Rightarrow Tr\left(AB\right)=Tr\left(BA\right)=30$