## Getting acquainted with metrics

For the set $$X$$ and function $$\rho\colon X^2 \to \mathbb R$$ determine whether the function $$\rho$$ is a metric.
$$X = \{1, 2, 3, 4, 5\}$$ a $$\rho$$ is given by the table:
$$X = \{1, 2, 3, 4, 5\}$$ a $$\rho$$ is given by the table: