tikz

\documentclass[UTF8]{article}
\usepackage{ctex}
\usepackage{geometry}
\usepackage{tikz}
\usepackage{pgfplots}
\geometry{a4paper,left=2cm,right=2cm,top=2cm,bottom=2cm} 
\newcommand*{\edge}{10}
\begin{document}

\begin{center} 

\begin{tikzpicture}[scale=0.8,samples=1000]
    \draw[help lines,very thin,color=gray!50] (-10,-15) grid (10,15);
    \node at (-0.2,-0.2){$O$};
    \draw[->](-10,0) -- (10,0) node[right] {$x$};
    \draw[->](0,-15) -- (0,15) node[above] {$y$};
    \draw[domain=-4:2,red] plot(\x,{exp(\x)}) node[right] {$y=e^x$};
    \draw[domain=-7:7,blue] plot(\x,{sin(\x r)}) node[right] {$y=sinx$};
\end{tikzpicture}
\end{center}

\end{document}