Most of the time, when we deal with vectors, we don't draw these arrows anymore.

多数情况下,当我们处理矢量时,就不再画出这些箭头了

耶鲁公开课 - 基础物理课程节选

Okay, so the rule for adding the two vectors is, you draw the first one and at the end of that first one, you begin the second one.

矢量的加法法则就是,先画出第一个矢量,然后在它的终点,再画第二个矢量

耶鲁公开课 - 基础物理课程节选