Display style in math mode
Whitespace in math mode – texblog
Whitespace in math mode
This section will cover how to typeset mathematics. It will also cover how to handle complicated equations and multiple equation environments. For many people the most useful part of LaTeX is the ability to typeset complex mathematical formulas. This is achieved by the use of two operating modes, paragraph and math mode. There is also a third mode called LR mode, however, this is rarely used by beginners and furthermore, is usually implicitly entered with other commands.
One of the greatest motivating forces for Donald Knuth when he began developing the original TeX system was to create something that allowed simple construction of mathematical formulae, while looking professional when printed. The fact that he succeeded was most probably why TeX and later on, LaTeX became so popular within the scientific community. Typesetting mathematics is one of LaTeX's greatest strengths. It is also a large topic due to the existence of so much mathematical notation. If your document requires only a few simple mathematical formulas, plain LaTeX has most of the tools that you will need.