One of the things that was interesting, when we were talking about the Sooka, was this idea that the Sooka should be weak enough and it would be destroyed if a big storm comes through.

有一件很有意思的事情，我们当时谈到了苏卡这个地方，意识到它其实很脆弱,很可能被即将到来的风暴摧毁。

普林斯顿公开课 - 人性课程节选

That means, when I take two derivatives, I want to get a, then you should know enough calculus to know it has to be something like at^, and half comes from taking two derivatives.

也就是说,当我想求二阶导时,得到了a,你应该有足够的微积分知识,才能知道必须有类似at^的项,而这个1/2则是因为求了两次导数

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