At every point of time your mortgage balance is equal to your mortgage payment times that square bracketed thing, where T is the amount of time you have left.

在每个时间点的抵押贷款余额,都等于每月偿还额乘以,方括号内的值,T是剩余年份数

耶鲁公开课 - 金融市场课程节选

As long as we understand that, we can do this cancellation and this says on the left-hand side the change in the quantity v square over 2 is a times the change in the quantity x.

只要我们明白这一点,我们就可以这样做简化,在等号左边,v^/2的变化量,为a乘以x的变化量

耶鲁公开课 - 基础物理课程节选