Problems

1. Find the transpose of matrix $C = \begin{pmatrix} 1 & 0 & 3 \\ 2 & -1 & 4 \end{pmatrix}$.
2. Calculate the determinant of $D = \begin{pmatrix} 2 & 5 \\ 1 & 3 \end{pmatrix}$.
3. If $I$ is the $2 \times 2$ identity matrix, compute $D \times I$.