Now this is when I want to stop for a second and I know that some of you, from past experience, are somewhat math phobic.

现在我们暂停一下,根据之前的教学经验,我知道有些人有数学恐惧症

耶鲁公开课 - 博弈论课程节选

This is what's called the Bohr radius, and we'll explain - hopefully we'll get to it today where this Bohr radius name comes from, but for now what you need to know is just that it's a constant, just treat it like a constant, and it turns out to be equal to or about 1/2 an angstrom.

它叫做玻尔半径，我们后面会解释,希望我们今天可以讲到,波尔半径这个名称的由来，但现在你们只要记住,它是一个常数，只要把它当做一个常数对待，它等于,或者是1/2埃。

麻省理工公开课 - 化学原理课程节选

Now you have to know from elementary calculus that v times dv/dt is really d by dt of v square over 2.

根据初等微积分知识你们得知道,v乘以dv/dt其实就是d/2)/dt

耶鲁公开课 - 基础物理课程节选