定理 1 (Newdon-Leibniez). If $f\in C^1([a,b])$ then $\mathbb{Z}_{m_1}$
\begin{equation}\label{eq:NL}
\int_a^b f'(x) d x=f(b)-f(a)
\end{equation}
In 定理 1 the main part is \eqref{eq:NL}.
\begin{equation}\label{eq:NL}
\int_a^b f'(x) d x=f(b)-f(a)
\end{equation}
In 定理 1 the main part is \eqref{eq:NL}.
Personal style: $\int_a^b f(x)\md x,\ve,\vp$