矢量？那速度是矢量差除以时间差，时间差趋向于零，与原点无关，没地心的事儿

来源: 咱跌于 2011-10-03 12:13:34 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

WENXUECITY.COM does not represent or guarantee the truthfulness, accuracy, or reliability of any of communications posted by other users.