LaTeX How-to Add line by line comments to math proofs Label \(Ax = b\) under a matrix Put comment lines Put horizontal spaces Put matrices Discussions Meaning of \quad What does a double ampersand (&&) mean? \begin{equation} vs \begin{equation*} Reference Mathematical Symbols Supported LaTex commands by MathJax Index Commands commands/ Environments environments/ MathJax mathjax/ amsmath amsmath/