I tried to post this:
$$\sqrt{\left(\frac{\partial g}{\partial x_i}e_{x_1}\right)^2+\dotso+\left(\frac{\partial g}{\partial x}_ie_{x_n}\right)^2}=\frac gn\sqrt{\left(\frac{e_{x_1}}{x_1}\right)^2+\dotso+\left(\frac{e_{x_n}}{x_n}\right)^2}\;.$$
in a comment. It renders correctly in a main post:
$$\sqrt{\left(\frac{\partial g}{\partial x_i}e_{x_1}\right)^2+\dotso+\left(\frac{\partial g}{\partial x}_ie_{x_n}\right)^2}=\frac gn\sqrt{\left(\frac{e_{x_1}}{x_1}\right)^2+\dotso+\left(\frac{e_{x_n}}{x_n}\right)^2}\;.$$
but is rendered as raw command sequences in a comment; see the first comment below.