We can very well create a PDF with the labels and Font, styling the Mathematical Functions.
To correct and to provide info.
These is will be labels. Not the text box - where user can enter data in the PDF.
In Design Morde.
We can use the Baseline shift to negative values to declare Variable X1 and X2.
The base line shift to Positive values will get us the Sq Root and Cubes of the variables.
Make sure, the font style in Symbol or Webdings.
Hope this helps you.
Complex formulas need a special language to be entered and displayed properly.
This will be impossible to to with regular text fields even if you use rich text.
Generally the language therefore is either MathML or LaTeX.
MathML is XML based such as the forms created with designer - sounds pretty close, isn't it?!
But wait, a research ended up with the fact that MathML is not supported by Designer or Acrobat/Reader etc., so you won't be able to use it.
Maybe you/someone can create own flash contents with the sources provided by http://www.fmath.info/ which than can be used in the Flash fields introduced with ADEP Designer (Designer 10).