Originally posted by joy4210 at 2011-07-11 10:06:19:
http://blog.sina.com.cn/s/blog_5e16f1770100gywd.html

Originally posted by guoguos_zhou at 2011-07-11 15:54:58:
\usepackage{tikz}
.
.
.
\begin{center}

\begin{tikzpicture}

\draw  (0,0) arc (0:135:1.5cm); %起始点：角度范围：半径


\end{tikzpicture}


\end{center}

Originally posted by onesupeng at 2011-07-12 14:49:13:
\begin{picture}(80,160)
\textcolor{white}{\put(0,0){\vector(0,1){120}} \put(0,0){\vector(1,0){90}}
\put(90,0){x} \put(0,120){y}
\put(-90,80){\line(1,0){180}}\put(0,0){\line(-1,0){90}}\textcolor{ ...