To be able to enter mathematical formula's in some text boxes of Matrix Requirements application, you need to insert a diagram within a rich text box. 

In the diagram tool, you need to select the "Mathematical Typesetting" to enable the mathematical syntax recognition :

The following syntax can be used: AsciiMath, LaTeX or Inline LaTeX, see more information on support:

Below, an example of an AsciiMath and LaTeX formula's: