Where can I test LaTeX functions on this website? Which forum? Thanks! :)
Why "test" it? If you want to use it to say something "mathematical", go ahead and do it!
You can test the validity of your input code using the feature "preview (reply)"(the button next to "submit")...If you see something wrong there,then you'd better check your code again...
People use the following thread as their LaTeX scratch pad:
Separate names with a comma.