有人能弄清楚为什么解决方案部分中的 (c) 部分在下一页编译吗？我该如何防止这种情况发生？谢谢！
以下是我的代码。
\documentclass[12pt]{article}
\usepackage{times} %font: new times roman
\usepackage{amsmath}
\usepackage{mathtools} %for flalign
\usepackage{eqparbox} %for eqparbox
\usepackage{unicode-math}
\setmainfont{XITS}
\setmathfont{XITS Math} %math font:XITS math
\pagenumbering{gobble} %no page no.
\usepackage[margin=50pt]{geometry} %set margin width
\setlength{\paperheight}{1200pt} %set page height
\usepackage{xcolor} %for colour
\setlength\parindent{0pt} %no paragraph indent
\usepackage{pgfplots}
\pgfplotsset{compat=1.15}
\usepackage{mathrsfs}
\usetikzlibrary{arrows}
\usepackage{caption}
\usepackage{enumitem}
\usetikzlibrary{shapes.misc}
% From http://tex.stackexchange.com/questions/123760/draw-crosses-in-tikz
\tikzset{cross/.style={cross out, draw=black, fill=none, minimum size=2*(#1-\pgflinewidth), inner sep=0pt, outer sep=0pt}, cross/.default={2pt}}
\begin{document}
Figure 1 shows the graph of $\displaystyle y = 9 x^2 + 6mx - k+1 $, where $ m < 0$. The graph touches the $x$-axis at the point $P$, and it cuts the $y$-axis at the point $Q$.
\begin{enumerate}[label = (\alph*)]
\item Show that $ k = 1 - m^2 $. \hfill \textbf{(2 marks)}
\item Find, in terms of $m$, the coordinates of $Q$ and $P$. \hfill \textbf{(3 marks)}
\item Find the values of $m$ and $k$ if the area of $\Delta OPQ$ is $\displaystyle \frac{4}{3}$ square units. \hfill \textbf{(2 marks)}
\end{enumerate}
\begin{figure}[h]
\centering
\begin{tikzpicture}[line cap=round,line join=round,>=triangle 45]
\begin{axis}[
ticks=none,
x=1cm,y=1cm,
axis lines=middle,
axis line style = very thick,
xmin=-2,
xmax=6,
ymin=-1,
ymax=7,
x label style={at={(current axis.right of origin)},anchor=north},
y label style={at={(current axis.above origin)},anchor=west},
xlabel={$x$},
ylabel={$y$}] %axis style setting
\addplot[samples = 200, domain={-1.6:5.6},line width=1pt] {0.5*(x-2)^2};
\draw (0,2) node[left] {$Q$} -- (2,0) node[below] {$P$} ;
\draw (0,0) node[anchor = north east] {$O$};
\draw (2.5,5) node {$ y = 9 x^2 + 6mx - k+1 $};
\end{axis}
\end{tikzpicture}
\captionsetup{labelformat=empty}
\caption{Figure 1}
\end{figure}
{
\color{red}
Solution:
\begin{enumerate}[label = (\alph*)]
\item
\begin{flalign*}
& & \Delta & = 0 &\\
& & (6m)^2 - 4(9)(-k+1) & = 0 & \eqparbox{C}{1M}\\
& & m^2 + k - 1 &= 0 & \\
& & k &= 1 - m^2 & \eqparbox{C}{1A}
\end{flalign*}
\item
When $x = 0$, $ y= -k + 1 = -1+m^2 + 1 = m^2$.\\
$\therefore$ $Q(0,m^2)$. \hfill 1A \\
When $y = 0$,
\begin{flalign*}
& & 0 &= 9x^2 + 6mx + m^2 &\\
& & 0 & = (3x + m)^2 & \eqparbox{C}{1M}\\
& & x & = -\frac{m}{3} &
\end{flalign*}
$\therefore$ $\displaystyle P \left( -\frac{m}{3},0\right) $. \hfill 1A
\item Area of $\Delta OPQ$ $\displaystyle = \frac{1}{2}(m^2)\left( -\frac{m}{3} \right) = -\frac{m^3}{6}$ \hfill 1M
\begin{flalign*}
& & -\frac{m^3}{6} & = \frac{4}{3} \\
& & m & = - 2 &
\end{flalign*}
$k = 1- (- 2)^2 = -3 $ \hfill 1A
\end{enumerate}
\end{document}
答案1
您需要 (a) 删除指令\setlength{\paperheight}{1200pt}并 (b) 更改\usepackage[margin=50pt]{geometry}为\usepackage[paperheight=1200pt, margin=50pt]{geometry}。
当您这样做时，也请删除该指令\usepackage{times}。