2. The covariance matrix is given by
$\begin{bmatrix} cov(x, x) & cov(x, y) \\ cov(y, x) & cov(y, y) \end{bmatrix} = \begin{bmatrix} var(x) & cov(x, y) \\ cov(y, x) & var(y) \end{bmatrix}$
Compute the covariance matrix for the following dataset
$D = \left\{ \begin{bmatrix} 1 \\ 2 \end{bmatrix}, \begin{bmatrix} 5 \\ 4 \end{bmatrix} \right\}$
Here, every column vector represents a data point.