Change the independent variable, find the change in the function, take the ratio and that's the derivative.

改变自变量,算出函数的变量,计算比值,这就是求导

耶鲁公开课 - 基础物理课程节选

In economics we can often observe the fact that a dependent variable is not always able to move immediately after a fortuitous change in an independent variable.

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The researchers carefully document data on Shariah law-adherence - the independent variable.

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It is a truly independent variable.

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