[help-texinfo] (math) fractions

[Nicolas Roche]

Hello,

I'm trying to print fractions using the @math command.
Within latex I can do:
 \[ \frac{a}{b} \]

I read in the texinfo manual that "In essence, |@math| drops you into 
plain TeX math mode."
But using texinfo, "make dvi" complains with:
@math{\frac{a}{b}}

Error is:
./supp.texi:9: Undefined control sequence.
<argument> \frac
                 {a}{b}
\finishmath #1->#1
                  $\endgroup
l.9 @math{\frac{a}{b}}

Is there a way to do that ?
Thanks.
Nicolas.