Hi, I compiled the following lines with xelatex(0.998.3) on miktex 2.7 and got a mistake in displaying radical symbol: \documentclass{article} \begin{document} $$\sqrt{x_1^2+x_2^2\ldots+x_n^2}$$ \end{document} The output is here http://www.omidali.com/sample.pdf Any comment is welcome