位场垂向二次导数是基于拉氏方程求得的。

The Second vertical derivative of the potential field is obtained from Lapace's equation.

youdao

基本上，答案就是，我们不可以用二次导数来验证这个情况。

Basically, the answer for us is that we don't have a second derivative test in this situation.

youdao

这里有一个测试的方法，但是它比二次导数复杂多了。

There is a criterion but it is much more complicated than that.

youdao

If you knew only the third derivative of the function, you can have something quadratic in t without changing the outcome.

如果方程里有三阶导数,你就可以引入一个二次项,但是结果却不会变

耶鲁公开课 - 基础物理课程节选

So here I've written for the hydrogen atom that deceptively simple form of the Schrodinger equation, where we don't actually write out the Hamiltonian operator, but you remember that's a series of second derivatives, so we have a differential equation that were actually dealing with.

这里我写出了,氢原子薛定谔方程的,最简单形式，这里我们实际上,没有写出哈密顿算符,但是请记住那你有，一系列的二次导数,所有我们实际上会处理一个微分方程。

麻省理工公开课 - 化学原理课程节选

I differentiate a second time and check the sign, so the second order condition, I differentiate this expression again with respect to q1.

我们对它进行二次求导然后看符号,这个式子的二阶导数,就是一阶导数再对q1进行求导

耶鲁公开课 - 博弈论课程节选