Question

$A=\left[\begin{array}{cccc}2& 0& 0& -1\\ 0& 1& 0& 0\\ 0& 0& 3& 0\\ -1& 0& 0& 4\end{array}\right]$. The sum of the eigen values of the matrix A is

• A. $10$
• B. $-10$
• C. $24$
• D. $22$

Answer 1

The correct option is A $10$

Sum of eigen values of any matrix [A] = sum of the diagonal elements of matrix = trace of matrix [A]
$\sum {\lambda }_i=2+1+3+4=10$