Size Math font – Define different sizes for Display and Text Equations globally

Question

I have a rather long document with plenty of maths and equations. As the equations are quite long I have chosen to use 8pt for equations in the display mode instead of the 10pt normal size.

\DeclareMathSizes{10}{8}{6}{6} globally changes all equations in math mode to 8pt font.

Is there a way to stick with 10pt in textstyle equations?, i.e. is it possible to differentiate between displaystyle and textstyle?

Help is much appreciated!

Answer 1

I'm not clear exactly what your question is but you ask in comments of it is possible to locally affect the size of formulae. The standard LaTeX font commands affect math as well as text so you can do this:

\documentclass{article}
\usepackage{amsmath}

\begin{document}

xxx $a=b$ yyy

zzz zzz zzz zzz zzz zzz 
\[a=b\]
yy yy yy yy yy yy yy yy 

zzz zzz zzz zzz zzz zzz 
{\small\[a=b\]}%
yy yy yy yy yy yy yy yy 

\end{document}