Google Chart Tools

http://code.google.com/intl/ja/apis/charttools/index.html

数式が簡単に書ける

http://chart.apis.google.com/chart?cht=tx&chl=x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}

#img(http://chart.apis.google.com/chart?cht=tx&chl=x=\frac{-b\pm\sqrt{b^2-4ac}}{2a})