My first blog entry describes how to use MathJax on SquareSpace, which allows the users browser to perfectly typeset mathematics on the fly. To tell MathJax to create an equation like $$y=3x+2,$$insert the following code
$$y=3x+2$$
into the text of the page.
The Pythagorean equation \begin{equation}a^2 + b^2 = c^2,\label{pyth}\end{equation} which holds for right triangles, is very important. This numbered equation was typeset as a LaTeX begin/end equation environment inserted directly into the text.
\begin{equation}a^2 + b^2 = c^2,\label{pyth}\end{equation}An equation inline with the text (e.g. $a^2 + b^2 = c^2$) is typeset using a single $.
Another important equation is \begin{equation} E = mc^2,\end{equation}although this formula is incomplete. The fully correct formula is \begin{equation} E^2 = m^2c^4 + p^2 c^2.\label{E2}\end{equation} Curiously, eq. \eqref{E2} is a version of the Pythagorean equation (eq. \eqref{pyth}) and says that, if mass and momentum are the two bases of a right triangle, then energy is the hypotenuse. I cross-referenced the equations by inserting a \label tag into the equation environment, and then using a matching \eqref tag in the text, just like LaTeX.
To enable MathJax with this configuration, I did a global code injection into the HEADER/FOOTER of every page in the website, which is detailed here.