If the rate of population growth of the United States between 1820 and 1850 had sustained over time, we'd have today approximately one and a half billion people in the United States.

如果在1820至1850年间,美国人口增长率保持下去的话,今天我们的美国,就会拥有近十五亿人口

耶鲁公开课 - 美国内战与重建课程节选

If the rate of growth had sustained, that's what the population would've been.

假如高增长率持续的话,我们现在得有多少人口啊

耶鲁公开课 - 美国内战与重建课程节选

This makes sense; the rate at which the cell population is growing, the derivative dX/dt, is proportional to the number of cells I have.

这个说的通,细胞数目的增长速度,就是导数dX/dt,和细胞数目呈比例关系

耶鲁公开课 - 生物医学工程探索课程节选

If X is the number of cells, then the rate of change of X, dX/dt, the rate of change of the cell population, how fast division is taking is proportional to the number of cells I have.

如果X是细胞数目,那么X的改变率就是dX/dt,就是细胞数目的改变率,分裂的速度有多快,和细胞数量呈比例关系

耶鲁公开课 - 生物医学工程探索课程节选