Tips for using LaTeX in comments

This blog uses the WP LaTeX plugin to render math.  The FAQ for the plugin gives some basic instructions:

WP LaTeX FAQ

Your LaTeX code should be placed between the two tags [latex] and [/latex]

You can use \\ for making multiline equations, but you can’t use & for aligning them. The plugin will refuse to parse this. As a workaround I use \phantom{1} plus the normal¬† LaTeX spacing commands like quad, etc.

Here is an unaligned multiline equation:

x^2 + y^2 = r^2\\=a^2

Here is the same thing, aligned by hand with \phantom{1} \ \ \qquad:

x^2 + y^2 = r^2\\ \phantom{1}\ \ \qquad  =a^2