In Emacs I frequently use math symbols when I write my theory summaries of math textbooks. I use org-mode to structure information and I know about at least two methods of enter
There's also latex-pretty-symbols, which may be a bit less finnicky.
M-x set-input-method RET TeX sounds like what you want.
View available symbols by executing M-x describe-input-method RET TeX (or its binding C-h I).
If you'll want to use this often, you can customize the variable default-input-method and set it to TeX. That way, you can activate the input method with C-\ (for toggle-input-method) in any buffer where you need it.