Practicing Success
If $A=\left[\begin{array}{cc}a & b \\ c & -a\end{array}\right]$ such that $A^2=I$ then which of the following is true? |
$1+a^2+b c=0$ $1-a^2+b c=0$ $1-a^2-b c=0$ $1+a^2-b c=0$ |
$1-a^2-b c=0$ |
The correct answer is Option (3) → $1-a^2-b c=0$ |