I am wondering Is there any better way to write math symbol in the source mode? Although I could use activate to preview the formula, I could not type in math symbols in the source mode. 

I normally just switch to generic mode, type all the math symbol I want, and then switch back to source mode, copy what I have typed into places. It requires to switch back and forth multiple times inefficiently if I get some bugs. Any suggestions? What is the typical way to write macros for math equations, especially to write math symbols(like calligraphy letters) in source mode?

Thanks.

Best,

Junsong