If I have the following term in my equation:
   Sqrt*(Faa^2-Fab^2)

If Fab^2 is larger than Faa^2 will the minus sign carries
with it? In other words, if Faa^2 is equal to 4 and Fab^2 is
equal to 25 will this term becomes sqrt (-20) and 
thus becomes -4.472?

Thanks for your help.

Ken Seto