I have been using the tags
\( and \)
for enclosing latex on anki desktop (≥ 2.1), however they don’t render in ankiweb (despite them being rendered using the JS library mathjax on anki desktop?!). I have also done the Tools->Check Media click like it was suggested somewhere on here. Now I have found this guide: niklaskorz .de /2017/06/studying-mathematics-with-anki-and-mathjax.html, which suggests putting a mathjax script tag in a custom template and this indeed works and renders in ankiweb but now those notes are not rendering in anki desktop. I am very frustrated to say the least 
happy for any help,
whiterock