2000017208

Let $x\in \mathbb{R}$. What is the sum of all the entries on the main diagonal of the following matrix? $$\left(\begin{array}{ccc}{\sin }^{2}x& 0& 1\\ 5& {\cos }^{2}x& 4\\ {\sin }^{2}x& 3& -1\end{array}\right)$$