\documentclass{article}\usepackage{amsmath}\usepackage{xepersian}\begin{document}\[\begin{pmatrix}\sum_{j=1}^{k_i}r_{i_j}a_js_{i_j}&\sum_{j=1}^{k_i}r_{i_j}a_js_{i_j}\\0&\sum_{j=1}^{k_i}r_{i_j}a_js_{i_j}\end{pmatrix}\]\end{document}