Question

The eigen values of matrix$A=\left[\begin{array}{cc}0& 1\\ 1& 0\end{array}\right]$ are

• A. $1,1$
• B. $-1,-1$
• C. $J,-J$
• D. $1,-1$

Answer 1

The correct option is D $1,-1$

Characteristic equation is $|A-\lambda I|=0$
$\lambda \left|\begin{array}{cc}-\lambda & 1\\ 1& -\lambda \end{array}\right|=0$
${\lambda }^2-1=0$
$\lambda =\pm 1$