{equations} is about the various environments to typeset displaystyle mathematics, e.g. equation and {align}. For general questions about mathematical typesetting use {math-mode}. Both tags are possible on the same question.
equations is about the various environments to typeset displaystyle mathematics, e.g. equation and align. For general questions about mathematical typesetting use math-mode. Both tags are possible on the same question.
Useful references for LaTeX users are Herbert Voß' Math mode and (if this recommended package is used) the amsmath user's guide.
