In the following matrix, what is the position of the entry with the largest value?
\[
\left (\array{
1+2& \sin \frac{\pi}4& \mathrm{tg}\,\frac{3\pi}4\cr
3+\cos \frac{\pi}2 & 2^{\sqrt3} & 5+\mathrm{tg} (-\pi)\cr
\sqrt{23}& 3-4 & \sin 2\pi -2
} \right )
\]
For what real value of \(a\) is the following matrix an upper triangular matrix?
\[
\left (\array{
2^{a-3}& 3+a& a-2\cr
3-a & (\sqrt3)^{a-1} & 1+a\cr
\sin (\pi a) & a-\sqrt9 & 2+\sqrt3
} \right )
\]
Let \(x \in \mathbb{R}\). What is the sum of all the entries on the main diagonal of the following matrix?
\[
\left (\array{
\sin^2 x& 0& 1\cr
5 & \cos^2 x & 4\cr
\sin^2 x & 3 & -1
} \right )
\]