<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; ">When, using amsmath I have the following source code:<DIV>*********************************************************************************</DIV><DIV>\begin{eqnarray*}</DIV><DIV>    \frac{1}{2}\int_{0}^{2\pi/3}\sin\theta\ d\theta </DIV><DIV>    &amp; =\frac{1}{2} \left(-\cos\theta\right) </DIV><DIV>    &amp; =-\frac{1}{2}\cos\frac{2\pi}{3}+\frac{1}{2}\cos0  \\</DIV><DIV>     &amp; =-\frac{1}{2} \left(-\frac{1}{2} \right)+\frac{1}{2} \left(1\right) &amp; =\frac{1}{4}.</DIV><DIV>\end{eqnarray*}</DIV><DIV>*********************************************************************************</DIV><DIV>the various fractions come out different sizes: in the first, third, and last group</DIV><DIV>they come out in what appears to be displaystyle, but in the second and next-to-last group</DIV><DIV>they come out markedly smaller.  What is going on?<BR><DIV> <SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><P style="margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px Helvetica; min-height: 14.0px"><BR></P><P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Zbigniew Nitecki</FONT></P><P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Department of Mathematics</FONT></P><P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Tufts University</FONT></P><P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Medford, MA 02155</FONT></P><P style="margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px Helvetica; min-height: 14.0px"><BR></P><P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">telephones:</FONT></P><P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Office<SPAN class="Apple-converted-space"><SPAN class="Apple-converted-tab">   <SPAN class="Apple-converted-space"> </SPAN></SPAN></SPAN>(617)627-3843</FONT></P><P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Dept.<SPAN class="Apple-converted-space"><SPAN class="Apple-converted-tab">   <SPAN class="Apple-converted-space"> </SPAN></SPAN></SPAN>(617)627-3234</FONT></P><P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Dept. fax<SPAN class="Apple-converted-space"><SPAN class="Apple-converted-tab">   <SPAN class="Apple-converted-space"> </SPAN></SPAN></SPAN>(617)627-3966</FONT></P><BR class="Apple-interchange-newline"></SPAN></SPAN> </DIV><BR></DIV></BODY></HTML>