接着，我们找最小值点，会发现它不是临界点。

But then, when we are looking for the minimum of a function, well, it is not at a critical point.

youdao

也就是说，如果你可以解出来或者去除掉这些变量的点，就是临界点，当你有这样的问题要解决的时候，我们找到临界点了，它们一定是最大值点或者最小值点吗？

That means if you were able to solve and eliminate the variable that would be a critical point. When you have the same problem, as we have critical points, are they maxima or minima?

youdao

而- 1正是这个临界点处的函数值，所以，这是一个最小值。

And minus one happens to be the value at the critical point. So, it is a minimum.

youdao