% !TEX encoding = UTF-8 Unicode
documentclass[a4paper,12pt]{report}
usepackage[utf8]{inputenc}
usepackage[T1]{fontenc}
usepackage{datetime}
usepackage[turkish]{babel}
usepackage{amsmath}
usepackage{amssymb}

begin{document}

begin{bmatrix}
a & b \
c & d
end{bmatrix}

end{document}