Question

If $A=\left[\begin{array}{cc}0& 1\\ -1& 0\end{array}\right]$ then determinant of $\left[A\right]$ is

• A. $1$
• B. $-1$
• C. $0$
• D. $2$

Answer 1

Answer: (A)

$1$

Determinants of a $2\times 2$ matrix is given by:

If $A=\left[\begin{array}{cc}a& b\\ c& d\end{array}\right]$

$Det\left(A\right)=ad-bc$

Hence using this above property:

If $A=\left[\begin{array}{cc}0& 1\\ -1& 0\end{array}\right]$, then

$Det\left(A\right)=0\times 0-1\times (-1)=0+1=1$