# how to render latex symbol in tex.stackexchange.com? [duplicate]

this piece of latex can be rendered correctly on math.stackexchange.com

$\operatorname{var}[\boldsymbol{\mathrm{AD}}+\mathbf{b}] = \boldsymbol{\mathrm{A}} \operatorname{var}[\boldsymbol{\mathrm{D}}]\boldsymbol{\mathrm{A}}^T$


gives this figure

how to render it correctly on tex.stackexchange.com?