In LaTeX a document is typeset one paragraph at a time and these paragraphs are broken into lines of equal width. So if you are using an 11pt font then the space provided by quadwill be 11pt horizontally of course The qquadgives twice that amount. For example in anintegral the tradition is to put a small extra space between thefxand the dx here done with the command.
- a medium space - a thin space.
If you want different spacing LaTeX provides the following four commands for use in math mode. The difference is almost unnoticeable. So if you are using an 11pt font then the space provided by quadwill be 11pt horizontally of course The qquadgives twice that amount. To make equation authoring easier iWork and iBooks Authors equation editors are in math mode by default so it isnt necessary to add math mode commands to your equations.