I take a look at the second derivative, which is the second order condition.

我需要求出二阶导数,即需要寻找二阶条件

耶鲁公开课 - 博弈论课程节选

I actually need to check the second order condition.

实际上我们还需要验证二阶条件

耶鲁公开课 - 博弈论课程节选

So how do I check the second order condition?

怎样验证二阶条件呢

耶鲁公开课 - 博弈论课程节选

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

So if we differentiate this object, I'm gonna find a first order condition in a second.

想要求它的导数,先让我想想一阶条件

耶鲁公开课 - 博弈论课程节选