From 63827b1b195d7a825d0a623583ba1305bc8cbf38 Mon Sep 17 00:00:00 2001
From: Didnelpsun <48906416+Didnelpsun@users.noreply.github.com>
Date: Mon, 11 Jan 2021 23:57:07 +0800
Subject: [PATCH] Update perpare.tex

---
 1.1-perpare/perpare.tex | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/1.1-perpare/perpare.tex b/1.1-perpare/perpare.tex
index 09aa1a9..170f919 100644
--- a/1.1-perpare/perpare.tex
+++ b/1.1-perpare/perpare.tex
@@ -35,6 +35,11 @@ $y=f(x)$，定义域为$D$，值域为$R$，若对于每一个$y\in R$，必然
 \end{enumerate}
 \subsection{复合函数}
 设$y=f(u)$的定义域为$D_1$，函数$u=g(x)$在$D$上有定义且$g(D)\in D$，则由$y=f[g(x)],x\in D$确定的函数称为由函数$u=g(x)$和函数$y=f(u)$构成的复合函数，定义域为D，u为中间变量。
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+\textbf{例题：}设$f(x)=x^2$，$f[\psi (x)]=-x^2+2x+3$，且$\psi (x)\geq 0$，求$\psi (x)$以及定义域与值域。
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 \subsection{有界性}
 \subsection{单调性}
 \subsection{奇偶性}