How to annotate an equation in latex?
An equation in LaTeX can be annotated using the \tag{} command. For example, the equation
\begin{equation}
x^2 + y^2 = z^2
\end{equation}
can be annotated as
\begin{equation}
x^2 + y^2 = z^2 \tag{Pythagorean Theorem}
\end{equation}