请问如何画出虚线?
我要下面两条是虚线:
O
/ \
口 O
(虚线) → / \←(虚线)
我是用这个方法画图
\draw node[circle,draw] (0) at (0,0) {\scriptsize $\alpha$};
\draw node[rectangle,draw] (1) at (-1,-1){\scriptsize };
\draw node[circle,draw] (2) at (1,-1) {\scriptsize };
\draw node(3) at (0,-2) {};
\draw node(4) at (2,-2) {};
\draw [-] (0) to (1);
\draw [-] (0) to (2);
\draw [.] (2) to (3);
\draw [.] (2) to (4);
拜托了><"

[.]改成[dashed]试试看

or [dotted]

感谢^^