latex之插入向量、图片、编号

1、向量

$\vec a$\qquad
$\overleftarrow{AB}$\qquad
$\overleftrightarrow{AB}$\qquad
$\overrightarrow{AB}$

2、插入图片

 \section{测试插入图片1}
 \includegraphics[scale=0.4]{noise.jpg}
 
 \section{测试插入图片2}
 \begin{figure}[ht]
 \includegraphics[scale=0.4]{noise.jpg}
 \caption{figure1. 测试图示2}
 \label{figl}
 \end{figure}
 
 \section{测试插入图片3}
 \begin{figure}[ht]
 \includegraphics[scale=1]{C:/Users/gaoyixue/Desktop/temp4.jpg}
 \end{figure}

3、插入编号

\begin{itemize}
    \item latex1
    \item latex2
    \item latex3
\end{itemize}
 
\begin{itemize}
    \item[1] latex1
    \item[2] latex2
    \item[3] latex3
\end{itemize}
 
\begin{enumerate}
    \item latex1
    \item latex2
    \item latex3
\end{enumerate}
 
\begin{enumerate}
    \item[(1)] latex1
    \item[(2)] latex2
    \item[(3)] latex3
\end{enumerate}