I used to use jsMath to support latex in this website, but it no longer works (I have no idea why). The one I am using right now in this blog is MathJax LaTex WordPress plugin. A pleasant surprise is that my old equations (e.g. in Balloon model) still work under this new plugin.
Update 2020/04/21: Now I disabled loading MathJax for every page. To enable it on a page, I need to have the mathjax shortcode anywhere in the page (Square brackets around mathjax).
To write an equation, use double dollar sign:
$$\int {1\over x}\,dx = \ln(x)+C$$
To write an in-line equation, use slash parenthesis: \(\alpha+\beta\geq\gamma=\pi\)
Let’s write the most beautiful equation ever:
$$e^{i\pi}+1=0$$
The source code is:
Here is my setting for MathJax LaTex plugin: