我有一堆简单的三角函数问题需要热身。你能创建一个全局变量\showAnswer 来接受true或false（默认）以显示和隐藏答案吗？
与其他解决方案相比，我更喜欢 TeX 解决方案。
\documentclass[12pt,a5paper,landscape]{article}
\usepackage[hmargin=5mm,vmargin=1.3cm]{geometry}
\usepackage{multicol}
\begin{document}
\begin{multicols}{3}
\begin{enumerate}
\item $\displaystyle \tan 15^\circ = 2-\sqrt{3}$
\item $\displaystyle \csc 300^\circ = -\frac{2}{\sqrt{3}}$
\item $\displaystyle \cos 255^\circ = -\frac{\sqrt{3}-1}{2 \sqrt{2}}$
\item $\displaystyle \cos 195^\circ = -\frac{1+\sqrt{3}}{2 \sqrt{2}}$
\item $\displaystyle \sec 135^\circ = -\sqrt{2}$
\item $\displaystyle \cos 330^\circ = \frac{\sqrt{3}}{2}$
\item $\displaystyle \tan 315^\circ = -1$
\item $\displaystyle \sec 75^\circ = \sqrt{2} \left(1+\sqrt{3}\right)$
\item $\displaystyle \tan 255^\circ = 2+\sqrt{3}$
\item $\displaystyle \csc 255^\circ = -\sqrt{2} \left(\sqrt{3}-1\right)$
\item $\displaystyle \csc 135^\circ = \sqrt{2}$
\item $\displaystyle \cos 120^\circ = -\frac{1}{2}$
\item $\displaystyle \tan 330^\circ = -\frac{1}{\sqrt{3}}$
\item $\displaystyle \sec 120^\circ = -2$
\item $\displaystyle \cot 315^\circ = -1$
\item $\displaystyle \sin 30^\circ = \frac{1}{2}$
\item $\displaystyle \sec 285^\circ = \sqrt{2} \left(1+\sqrt{3}\right)$
\item $\displaystyle \csc 195^\circ = -\sqrt{2} \left(1+\sqrt{3}\right)$
\item $\displaystyle \cot 180^\circ = \infty$
\item $\displaystyle \cot 330^\circ = -\sqrt{3}$
\item $\displaystyle \sec 0^\circ = 1$
\item $\displaystyle \cos 210^\circ = -\frac{\sqrt{3}}{2}$
\item $\displaystyle \sin 165^\circ = \frac{\sqrt{3}-1}{2 \sqrt{2}}$
\item $\displaystyle \sin 15^\circ = \frac{\sqrt{3}-1}{2 \sqrt{2}}$
\item $\displaystyle \sin 90^\circ = 1$
\item $\displaystyle \sin 225^\circ = -\frac{1}{\sqrt{2}}$
\item $\displaystyle \cot 75^\circ = 2-\sqrt{3}$
\item $\displaystyle \tan 240^\circ = \sqrt{3}$
\item $\displaystyle \sin 210^\circ = -\frac{1}{2}$
\item $\displaystyle \cos 270^\circ = 0$
\item $\displaystyle \sin 255^\circ = -\frac{1+\sqrt{3}}{2 \sqrt{2}}$
\item $\displaystyle \sec 270^\circ = \infty$
\item $\displaystyle \sin 285^\circ = -\frac{1+\sqrt{3}}{2 \sqrt{2}}$
\item $\displaystyle \tan 285^\circ = -2-\sqrt{3}$
\item $\displaystyle \csc 165^\circ = \sqrt{2} \left(1+\sqrt{3}\right)$
\item $\displaystyle \sec 45^\circ = \sqrt{2}$
\item $\displaystyle \sin 345^\circ = -\frac{\sqrt{3}-1}{2 \sqrt{2}}$
\item $\displaystyle \csc 180^\circ = \infty$
\item $\displaystyle \cos 180^\circ = -1$
\item $\displaystyle \cot 105^\circ = \sqrt{3}-2$
\item $\displaystyle \tan 30^\circ = \frac{1}{\sqrt{3}}$
\item $\displaystyle \sec 330^\circ = \frac{2}{\sqrt{3}}$
\item $\displaystyle \csc 150^\circ = 2$
\item $\displaystyle \sin 180^\circ = 0$
\item $\displaystyle \cos 285^\circ = \frac{\sqrt{3}-1}{2 \sqrt{2}}$
\item $\displaystyle \cos 15^\circ = \frac{1+\sqrt{3}}{2 \sqrt{2}}$
\item $\displaystyle \tan 225^\circ = 1$
\item $\displaystyle \cot 300^\circ = -\frac{1}{\sqrt{3}}$
\item $\displaystyle \cot 135^\circ = -1$
\item $\displaystyle \sec 60^\circ = 2$
\item $\displaystyle \sin 195^\circ = -\frac{\sqrt{3}-1}{2 \sqrt{2}}$
\item $\displaystyle \cot 120^\circ = -\frac{1}{\sqrt{3}}$
\item $\displaystyle \cos 165^\circ = -\frac{1+\sqrt{3}}{2 \sqrt{2}}$
\item $\displaystyle \sec 240^\circ = -2$
\item $\displaystyle \cos 240^\circ = -\frac{1}{2}$
\item $\displaystyle \csc 75^\circ = \sqrt{2} \left(\sqrt{3}-1\right)$
\item $\displaystyle \tan 90^\circ = \infty$
\item $\displaystyle \cos 225^\circ = -\frac{1}{\sqrt{2}}$
\item $\displaystyle \tan 105^\circ = -2-\sqrt{3}$
\item $\displaystyle \tan 195^\circ = 2-\sqrt{3}$
\item $\displaystyle \cot 210^\circ = \sqrt{3}$
\item $\displaystyle \cos 75^\circ = \frac{\sqrt{3}-1}{2 \sqrt{2}}$
\item $\displaystyle \cot 195^\circ = 2+\sqrt{3}$
\item $\displaystyle \sec 345^\circ = -\sqrt{2} \left(1-\sqrt{3}\right)$
\item $\displaystyle \sec 105^\circ = -\sqrt{2} \left(1+\sqrt{3}\right)$
\item $\displaystyle \cot 270^\circ = 0$
\item $\displaystyle \cos 135^\circ = -\frac{1}{\sqrt{2}}$
\item $\displaystyle \csc 240^\circ = -\frac{2}{\sqrt{3}}$
\item $\displaystyle \sec 315^\circ = \sqrt{2}$
\item $\displaystyle \cot 150^\circ = -\sqrt{3}$
\item $\displaystyle \cot 45^\circ = 1$
\item $\displaystyle \sin 135^\circ = \frac{1}{\sqrt{2}}$
\item $\displaystyle \csc 315^\circ = -\sqrt{2}$
\item $\displaystyle \sec 15^\circ = \sqrt{2} \left(\sqrt{3}-1\right)$
\item $\displaystyle \sec 180^\circ = -1$
\item $\displaystyle \sec 300^\circ = 2$
\item $\displaystyle \csc 330^\circ = -2$
\item $\displaystyle \csc 45^\circ = \sqrt{2}$
\item $\displaystyle \csc 285^\circ = \sqrt{2} \left(1-\sqrt{3}\right)$
\item $\displaystyle \sec 195^\circ = -\sqrt{2} \left(\sqrt{3}-1\right)$
\item $\displaystyle \csc 15^\circ = \sqrt{2} \left(1+\sqrt{3}\right)$
\item $\displaystyle \sec 255^\circ = -\sqrt{2} \left(1+\sqrt{3}\right)$
\item $\displaystyle \sin 60^\circ = \frac{\sqrt{3}}{2}$
\item $\displaystyle \sec 150^\circ = -\frac{2}{\sqrt{3}}$
\item $\displaystyle \cot 90^\circ = 0$
\item $\displaystyle \sin 0^\circ = 0$
\item $\displaystyle \cot 30^\circ = \sqrt{3}$
\item $\displaystyle \csc 270^\circ = -1$
\item $\displaystyle \sec 90^\circ = \infty$
\item $\displaystyle \tan 0^\circ = 0$
\item $\displaystyle \cos 345^\circ = \frac{1+\sqrt{3}}{2 \sqrt{2}}$
\item $\displaystyle \sin 300^\circ = -\frac{\sqrt{3}}{2}$
\item $\displaystyle \csc 60^\circ = \frac{2}{\sqrt{3}}$
\item $\displaystyle \tan 210^\circ = \frac{1}{\sqrt{3}}$
\item $\displaystyle \cos 300^\circ = \frac{1}{2}$
\item $\displaystyle \tan 75^\circ = 2+\sqrt{3}$
\item $\displaystyle \tan 345^\circ = \sqrt{3}-2$
\item $\displaystyle \sin 45^\circ = \frac{1}{\sqrt{2}}$
\item $\displaystyle \cos 30^\circ = \frac{\sqrt{3}}{2}$
\item $\displaystyle \sec 210^\circ = -\frac{2}{\sqrt{3}}$
\item $\displaystyle \cot 165^\circ = -2-\sqrt{3}$
\item $\displaystyle \sin 75^\circ = \frac{1+\sqrt{3}}{2 \sqrt{2}}$
\item $\displaystyle \cos 0^\circ = 1$
\item $\displaystyle \cot 285^\circ = \sqrt{3}-2$
\item $\displaystyle \cot 60^\circ = \frac{1}{\sqrt{3}}$
\item $\displaystyle \sin 270^\circ = -1$
\item $\displaystyle \cos 315^\circ = \frac{1}{\sqrt{2}}$
\item $\displaystyle \csc 345^\circ = -\sqrt{2} \left(1+\sqrt{3}\right)$
\item $\displaystyle \tan 180^\circ = 0$
\item $\displaystyle \cot 15^\circ = 2+\sqrt{3}$
\item $\displaystyle \csc 30^\circ = 2$
\item $\displaystyle \tan 165^\circ = \sqrt{3}-2$
\item $\displaystyle \tan 300^\circ = -\sqrt{3}$
\item $\displaystyle \tan 120^\circ = -\sqrt{3}$
\item $\displaystyle \sin 330^\circ = -\frac{1}{2}$
\item $\displaystyle \csc 0^\circ = \infty$
\item $\displaystyle \tan 150^\circ = -\frac{1}{\sqrt{3}}$
\item $\displaystyle \sec 30^\circ = \frac{2}{\sqrt{3}}$
\item $\displaystyle \sin 315^\circ = -\frac{1}{\sqrt{2}}$
\item $\displaystyle \cot 225^\circ = 1$
\item $\displaystyle \cos 45^\circ = \frac{1}{\sqrt{2}}$
\item $\displaystyle \cot 255^\circ = 2-\sqrt{3}$
\item $\displaystyle \cot 0^\circ = \infty$
\item $\displaystyle \cos 150^\circ = -\frac{\sqrt{3}}{2}$
\item $\displaystyle \sin 240^\circ = -\frac{\sqrt{3}}{2}$
\item $\displaystyle \csc 120^\circ = \frac{2}{\sqrt{3}}$
\item $\displaystyle \cot 240^\circ = \frac{1}{\sqrt{3}}$
\item $\displaystyle \sin 105^\circ = \frac{1+\sqrt{3}}{2 \sqrt{2}}$
\item $\displaystyle \csc 90^\circ = 1$
\item $\displaystyle \csc 105^\circ = -\sqrt{2} \left(1-\sqrt{3}\right)$
\item $\displaystyle \cos 60^\circ = \frac{1}{2}$
\item $\displaystyle \sec 225^\circ = -\sqrt{2}$
\item $\displaystyle \tan 135^\circ = -1$
\item $\displaystyle \tan 45^\circ = 1$
\item $\displaystyle \cot 345^\circ = -2-\sqrt{3}$
\item $\displaystyle \tan 270^\circ = \infty$
\item $\displaystyle \cos 105^\circ = -\frac{\sqrt{3}-1}{2 \sqrt{2}}$
\item $\displaystyle \tan 60^\circ = \sqrt{3}$
\item $\displaystyle \sin 120^\circ = \frac{\sqrt{3}}{2}$
\item $\displaystyle \cos 90^\circ = 0$
\item $\displaystyle \sec 165^\circ = \sqrt{2} \left(1-\sqrt{3}\right)$
\item $\displaystyle \csc 210^\circ = -2$
\item $\displaystyle \csc 225^\circ = -\sqrt{2}$
\item $\displaystyle \sin 150^\circ = \frac{1}{2}$
\end{enumerate}
\end{multicols}
\end{document}
答案1
在这里，在multicols环境中，我使其处于=活动状态，并且根据\showanswer（T或F）的值，我显示答案或\phantom答案的。
这种方法依赖于每个答案只有一个=，并且使用$数学分隔符（例如，而不是\(...\)）。
关键代码……事实上，OP 的 MWE 的唯一变化是：在序言中，
\newif\ifshowanswer
%\showanswertrue
\let\sveq==
在multicols环境中，
\catcode`\= \active
\ifshowanswer \def=#1${\sveq#1$}\else\def=#1${\sveq\phantom{#1}$}\fi
妇女权利委员会：
\documentclass[12pt,a5paper,landscape]{article}
\usepackage[hmargin=5mm,vmargin=1.3cm]{geometry}
\usepackage{multicol}
\newif\ifshowanswer
%\showanswertrue
\let\sveq==
\begin{document}
\begin{multicols}{3}
\catcode`\= \active
\ifshowanswer \def=#1${\sveq#1$}\else\def=#1${\sveq\phantom{#1}$}\fi
\begin{enumerate}
\item $\displaystyle \tan 15^\circ = 2-\sqrt{3}$
\item $\displaystyle \csc 300^\circ = -\frac{2}{\sqrt{3}}$
\item $\displaystyle \cos 255^\circ = -\frac{\sqrt{3}-1}{2 \sqrt{2}}$
\item $\displaystyle \cos 195^\circ = -\frac{1+\sqrt{3}}{2 \sqrt{2}}$
\item $\displaystyle \sec 135^\circ = -\sqrt{2}$
\item $\displaystyle \cos 330^\circ = \frac{\sqrt{3}}{2}$
\item $\displaystyle \tan 315^\circ = -1$
\item $\displaystyle \sec 75^\circ = \sqrt{2} \left(1+\sqrt{3}\right)$
\item $\displaystyle \tan 255^\circ = 2+\sqrt{3}$
\item $\displaystyle \csc 255^\circ = -\sqrt{2} \left(\sqrt{3}-1\right)$
\item $\displaystyle \csc 135^\circ = \sqrt{2}$
\item $\displaystyle \cos 120^\circ = -\frac{1}{2}$
\item $\displaystyle \tan 330^\circ = -\frac{1}{\sqrt{3}}$
\item $\displaystyle \sec 120^\circ = -2$
\item $\displaystyle \cot 315^\circ = -1$
\item $\displaystyle \sin 30^\circ = \frac{1}{2}$
\item $\displaystyle \sec 285^\circ = \sqrt{2} \left(1+\sqrt{3}\right)$
\item $\displaystyle \csc 195^\circ = -\sqrt{2} \left(1+\sqrt{3}\right)$
\item $\displaystyle \cot 180^\circ = \infty$
\item $\displaystyle \cot 330^\circ = -\sqrt{3}$
\item $\displaystyle \sec 0^\circ = 1$
\item $\displaystyle \cos 210^\circ = -\frac{\sqrt{3}}{2}$
\item $\displaystyle \sin 165^\circ = \frac{\sqrt{3}-1}{2 \sqrt{2}}$
\item $\displaystyle \sin 15^\circ = \frac{\sqrt{3}-1}{2 \sqrt{2}}$
\item $\displaystyle \sin 90^\circ = 1$
\item $\displaystyle \sin 225^\circ = -\frac{1}{\sqrt{2}}$
\item $\displaystyle \cot 75^\circ = 2-\sqrt{3}$
\item $\displaystyle \tan 240^\circ = \sqrt{3}$
\item $\displaystyle \sin 210^\circ = -\frac{1}{2}$
\item $\displaystyle \cos 270^\circ = 0$
\item $\displaystyle \sin 255^\circ = -\frac{1+\sqrt{3}}{2 \sqrt{2}}$
\item $\displaystyle \sec 270^\circ = \infty$
\item $\displaystyle \sin 285^\circ = -\frac{1+\sqrt{3}}{2 \sqrt{2}}$
\item $\displaystyle \tan 285^\circ = -2-\sqrt{3}$
\item $\displaystyle \csc 165^\circ = \sqrt{2} \left(1+\sqrt{3}\right)$
\item $\displaystyle \sec 45^\circ = \sqrt{2}$
\item $\displaystyle \sin 345^\circ = -\frac{\sqrt{3}-1}{2 \sqrt{2}}$
\item $\displaystyle \csc 180^\circ = \infty$
\item $\displaystyle \cos 180^\circ = -1$
\item $\displaystyle \cot 105^\circ = \sqrt{3}-2$
\item $\displaystyle \tan 30^\circ = \frac{1}{\sqrt{3}}$
\item $\displaystyle \sec 330^\circ = \frac{2}{\sqrt{3}}$
\item $\displaystyle \csc 150^\circ = 2$
\item $\displaystyle \sin 180^\circ = 0$
\item $\displaystyle \cos 285^\circ = \frac{\sqrt{3}-1}{2 \sqrt{2}}$
\item $\displaystyle \cos 15^\circ = \frac{1+\sqrt{3}}{2 \sqrt{2}}$
\item $\displaystyle \tan 225^\circ = 1$
\item $\displaystyle \cot 300^\circ = -\frac{1}{\sqrt{3}}$
\item $\displaystyle \cot 135^\circ = -1$
\item $\displaystyle \sec 60^\circ = 2$
\item $\displaystyle \sin 195^\circ = -\frac{\sqrt{3}-1}{2 \sqrt{2}}$
\item $\displaystyle \cot 120^\circ = -\frac{1}{\sqrt{3}}$
\item $\displaystyle \cos 165^\circ = -\frac{1+\sqrt{3}}{2 \sqrt{2}}$
\item $\displaystyle \sec 240^\circ = -2$
\item $\displaystyle \cos 240^\circ = -\frac{1}{2}$
\item $\displaystyle \csc 75^\circ = \sqrt{2} \left(\sqrt{3}-1\right)$
\item $\displaystyle \tan 90^\circ = \infty$
\item $\displaystyle \cos 225^\circ = -\frac{1}{\sqrt{2}}$
\item $\displaystyle \tan 105^\circ = -2-\sqrt{3}$
\item $\displaystyle \tan 195^\circ = 2-\sqrt{3}$
\item $\displaystyle \cot 210^\circ = \sqrt{3}$
\item $\displaystyle \cos 75^\circ = \frac{\sqrt{3}-1}{2 \sqrt{2}}$
\item $\displaystyle \cot 195^\circ = 2+\sqrt{3}$
\item $\displaystyle \sec 345^\circ = -\sqrt{2} \left(1-\sqrt{3}\right)$
\item $\displaystyle \sec 105^\circ = -\sqrt{2} \left(1+\sqrt{3}\right)$
\item $\displaystyle \cot 270^\circ = 0$
\item $\displaystyle \cos 135^\circ = -\frac{1}{\sqrt{2}}$
\item $\displaystyle \csc 240^\circ = -\frac{2}{\sqrt{3}}$
\item $\displaystyle \sec 315^\circ = \sqrt{2}$
\item $\displaystyle \cot 150^\circ = -\sqrt{3}$
\item $\displaystyle \cot 45^\circ = 1$
\item $\displaystyle \sin 135^\circ = \frac{1}{\sqrt{2}}$
\item $\displaystyle \csc 315^\circ = -\sqrt{2}$
\item $\displaystyle \sec 15^\circ = \sqrt{2} \left(\sqrt{3}-1\right)$
\item $\displaystyle \sec 180^\circ = -1$
\item $\displaystyle \sec 300^\circ = 2$
\item $\displaystyle \csc 330^\circ = -2$
\item $\displaystyle \csc 45^\circ = \sqrt{2}$
\item $\displaystyle \csc 285^\circ = \sqrt{2} \left(1-\sqrt{3}\right)$
\item $\displaystyle \sec 195^\circ = -\sqrt{2} \left(\sqrt{3}-1\right)$
\item $\displaystyle \csc 15^\circ = \sqrt{2} \left(1+\sqrt{3}\right)$
\item $\displaystyle \sec 255^\circ = -\sqrt{2} \left(1+\sqrt{3}\right)$
\item $\displaystyle \sin 60^\circ = \frac{\sqrt{3}}{2}$
\item $\displaystyle \sec 150^\circ = -\frac{2}{\sqrt{3}}$
\item $\displaystyle \cot 90^\circ = 0$
\item $\displaystyle \sin 0^\circ = 0$
\item $\displaystyle \cot 30^\circ = \sqrt{3}$
\item $\displaystyle \csc 270^\circ = -1$
\item $\displaystyle \sec 90^\circ = \infty$
\item $\displaystyle \tan 0^\circ = 0$
\item $\displaystyle \cos 345^\circ = \frac{1+\sqrt{3}}{2 \sqrt{2}}$
\item $\displaystyle \sin 300^\circ = -\frac{\sqrt{3}}{2}$
\item $\displaystyle \csc 60^\circ = \frac{2}{\sqrt{3}}$
\item $\displaystyle \tan 210^\circ = \frac{1}{\sqrt{3}}$
\item $\displaystyle \cos 300^\circ = \frac{1}{2}$
\item $\displaystyle \tan 75^\circ = 2+\sqrt{3}$
\item $\displaystyle \tan 345^\circ = \sqrt{3}-2$
\item $\displaystyle \sin 45^\circ = \frac{1}{\sqrt{2}}$
\item $\displaystyle \cos 30^\circ = \frac{\sqrt{3}}{2}$
\item $\displaystyle \sec 210^\circ = -\frac{2}{\sqrt{3}}$
\item $\displaystyle \cot 165^\circ = -2-\sqrt{3}$
\item $\displaystyle \sin 75^\circ = \frac{1+\sqrt{3}}{2 \sqrt{2}}$
\item $\displaystyle \cos 0^\circ = 1$
\item $\displaystyle \cot 285^\circ = \sqrt{3}-2$
\item $\displaystyle \cot 60^\circ = \frac{1}{\sqrt{3}}$
\item $\displaystyle \sin 270^\circ = -1$
\item $\displaystyle \cos 315^\circ = \frac{1}{\sqrt{2}}$
\item $\displaystyle \csc 345^\circ = -\sqrt{2} \left(1+\sqrt{3}\right)$
\item $\displaystyle \tan 180^\circ = 0$
\item $\displaystyle \cot 15^\circ = 2+\sqrt{3}$
\item $\displaystyle \csc 30^\circ = 2$
\item $\displaystyle \tan 165^\circ = \sqrt{3}-2$
\item $\displaystyle \tan 300^\circ = -\sqrt{3}$
\item $\displaystyle \tan 120^\circ = -\sqrt{3}$
\item $\displaystyle \sin 330^\circ = -\frac{1}{2}$
\item $\displaystyle \csc 0^\circ = \infty$
\item $\displaystyle \tan 150^\circ = -\frac{1}{\sqrt{3}}$
\item $\displaystyle \sec 30^\circ = \frac{2}{\sqrt{3}}$
\item $\displaystyle \sin 315^\circ = -\frac{1}{\sqrt{2}}$
\item $\displaystyle \cot 225^\circ = 1$
\item $\displaystyle \cos 45^\circ = \frac{1}{\sqrt{2}}$
\item $\displaystyle \cot 255^\circ = 2-\sqrt{3}$
\item $\displaystyle \cot 0^\circ = \infty$
\item $\displaystyle \cos 150^\circ = -\frac{\sqrt{3}}{2}$
\item $\displaystyle \sin 240^\circ = -\frac{\sqrt{3}}{2}$
\item $\displaystyle \csc 120^\circ = \frac{2}{\sqrt{3}}$
\item $\displaystyle \cot 240^\circ = \frac{1}{\sqrt{3}}$
\item $\displaystyle \sin 105^\circ = \frac{1+\sqrt{3}}{2 \sqrt{2}}$
\item $\displaystyle \csc 90^\circ = 1$
\item $\displaystyle \csc 105^\circ = -\sqrt{2} \left(1-\sqrt{3}\right)$
\item $\displaystyle \cos 60^\circ = \frac{1}{2}$
\item $\displaystyle \sec 225^\circ = -\sqrt{2}$
\item $\displaystyle \tan 135^\circ = -1$
\item $\displaystyle \tan 45^\circ = 1$
\item $\displaystyle \cot 345^\circ = -2-\sqrt{3}$
\item $\displaystyle \tan 270^\circ = \infty$
\item $\displaystyle \cos 105^\circ = -\frac{\sqrt{3}-1}{2 \sqrt{2}}$
\item $\displaystyle \tan 60^\circ = \sqrt{3}$
\item $\displaystyle \sin 120^\circ = \frac{\sqrt{3}}{2}$
\item $\displaystyle \cos 90^\circ = 0$
\item $\displaystyle \sec 165^\circ = \sqrt{2} \left(1-\sqrt{3}\right)$
\item $\displaystyle \csc 210^\circ = -2$
\item $\displaystyle \csc 225^\circ = -\sqrt{2}$
\item $\displaystyle \sin 150^\circ = \frac{1}{2}$
\end{enumerate}
\end{multicols}
\end{document}
错误版本
真实版本
正如我在后来的评论中指出的那样，我这样做是为了让空白答案占据与答案存在时完全相同的空间。否则，当将 showanswer 从 false 更改为 true 时会发生重新分页。如果您希望空白答案表提供统一的空间，您可以将一行替换为：\ifshowanswer \def=#1${\sveq#1$}\else\def=#1${\sveq$}\fi，删除\phantom{#1}。