Bug Latex fractions too big

nvn

I noticed at some point in time (I don't know when), fractions in PF latex became too big.

[tex]t=\frac{2}{3}(\sin x)(\frac{7}{4}\ +\ \frac{3}{58}\sin^2x)
\ +\ \frac{9}{7}\ln(\frac{3}{8}\,x)\ -\ \frac{5}{16}\ln(\frac{1}{8})[/tex]

How can I (easily) make the fractions slightly smaller, but not make any other characters or symbols any smaller? \tfrac makes the fractions too small, but \frac currently makes them too big. Older posts show fractions, using \frac, were slightly smaller, and closer to the normal size. Could PF go back to the old size for fractions, which were slightly smaller? Thanks for any help.