LaTeX is a tool that allows relatively easy expression of advanced mathematical formulae in Sakai. Before trying to use LaTeX in any Sakai tool, go to Site Info, then Manage Tools, then look on the lower right for Enable MathJax for automatic rendering of LaTeX and AsciiMath in this site. Make sure the box next to Enable MathJax  is selected. If it isn’t, click on the box and then select Continue and Finish. 

Once MathJax has been enabled, you can use LaTeX in many tools including Lessons, Tests & Quizzes, Assignments, and Conversations. 

You can use LaTeX in Conversations in both questions and answers to questions. Type LaTeX directly into the edit window (starting with $$); it will display on a separate line from other content and there will be no preview. After you save the post, you should see the expected LaTeX display. Alternatively, select the sigma character in the row of editing tools, and you can type in your LaTeX with a preview and have it display inline.