# Difference between revisions of "Euclidean metric"

The Euclidean metric on $\mathbb{R}^n$ is the standard metric on this space. The distance $d(\mathbf{x, y})$ between two elements $\mathbf{x} = (x_1, x_2, \ldots, x_n)$ and $\mathbf{y} = (y_1, y_2, \ldots, y_n)$ is given by $d(\mathbf{x, y}) = \sqrt{(x_1 - y_1)^2 + (x_2 - y_2)^2 + \ldots + (x_n - y_n)^2}$. It is straight-forward to show that this is symmetric, non-negative, and 0 if and only if $\mathbf{x = y}$. Showing that the triangle inequality holds true is somewhat more difficult, although it should be intuitively clear because it is properties of the Euclidean metric which motivate the definition of a metric.