답변1
패키지를 사용하여 stackengine
:
\documentclass{article}
\usepackage{amsmath, amssymb, bm}
\usepackage{stackengine}
\begin{document}
\begin{equation}
\stackMath
\nabla_{\theta}\bm{J}(\theta)
= \stackunder{\mathbb{E}}{\substack{s\sim T^{\bm{\pi}},\\
a \sim \bm{\pi}_{\theta}}}
[\nabla_{\theta}\log\bm{\pi}(a|s) \cdot Q(s,a)],
\end{equation}
\end{document}