添加白线以对齐环境

Question

我想在下面代码的两个方程式之间添加一条白线。我尝试过的所有方法都导致白线被列为附加方程式。

\begin{align}
\begin{split}
{}&\int_{-T}^{T} a_n \cos{(\tfrac{n\pi}{T}t)}dt=\frac{a_nT}{n\pi}\cdot- 
\sin{(\tfrac{n\pi}{T}t)}\rvert_{-T}^T=\\
%
&-\frac{a_nT}{n\pi}\cdot\lbrack\sin{(n\pi)}-\sin{(-n\pi)}\rbrack=\frac{a_nT} 
{n\pi}\cdot\lbrack0-0\rbrack=0
\end{split}\\
%I'd like a white line here, separating the two equations more clearly. It needs to be exactly the size of 1 normal white space.
\begin{split}
{}&\int_{-T}^{T} b_n \sin{(\tfrac{n\pi}{T}t)} dt=\frac{b_nT} 
{n\pi}\cdot\cos{(\tfrac{n\pi}{T}t)}\rvert_{-T}^T=\\
%
&\frac{b_nT}{n\pi}\cdot\lbrack\cos{(n\pi)}-\cos{(-n\pi)}\rbrack=\frac{b_nT} 
{n\pi}\cdot\lbrack\cos{(n\pi)}-\cos{(n\pi)}\rbrack=0
\end{split}
\end{align}

Answer 1

\\正如@campa 所建议的，你可以用\\[4ex]以下方法代替分离：

\documentclass[11pt]{article}
\usepackage{mathtools}

\begin{document}

\begin{align}
\begin{split}
{}&\int_{-T}^{T} a_n \cos{(\tfrac{n\pi}{T}t)}dt=\frac{a_nT}{n\pi}\cdot-
\sin{(\tfrac{n\pi}{T}t)}\rvert_{-T}^T=\\
%
&-\frac{a_nT}{n\pi}\cdot\lbrack\sin{(n\pi)}-\sin{(-n\pi)}\rbrack=\frac{a_nT}
{n\pi}\cdot\lbrack0-0\rbrack=0
\end{split}\\[4ex]
%I'd like a white line here, separating the two equations more clearly. It needs to be exactly the size of 1 normal white space.
\begin{split}
{}&\int_{-T}^{T} b_n \sin{(\tfrac{n\pi}{T}t)} dt=\frac{b_nT}
{n\pi}\cdot\cos{(\tfrac{n\pi}{T}t)}\rvert_{-T}^T=\\
%
&\frac{b_nT}{n\pi}\cdot\lbrack\cos{(n\pi)}-\cos{(-n\pi)}\rbrack=\frac{b_nT}
{n\pi}\cdot\lbrack\cos{(n\pi)}-\cos{(n\pi)}\rbrack=0
\end{split}
\end{align}

\end{document}