I cannot draw it that well, but imagine bringing the second point closer and closer to the first one.

我不能很好地把它画出来,但是你们可以想象,当第二个点,越来越靠近第一个点时

耶鲁公开课 - 基础物理课程节选

I cannot draw it that well, but imagine bringing the second point closer and closer to the first one.

我不能很好地把它画出来,但是你们可以想象,当第二个点,越来越靠近第一个点时

耶鲁公开课 - 基础物理课程节选