Question

If $A=\left[\begin{array}{ccc}1& -5& 7\\ 0& 7& 9\\ 11& 8& 9\end{array}\right]$ then the trace of the matrix is

Answer 1

The trace of matrix A is given by

Given $A=\left[\begin{array}{ccc}1& -5& 7\\ 0& 7& 9\\ 11& 8& 9\end{array}\right]$

Trace $T_r\left(A\right)$$=$ Sum of diagonal elements

Diagonal elements are $1,7and9$

$T_r\left(A\right)$ $=$$(1+7+9)$

$=$ $17$

Hence the trace of matrix $A$is $17$