# chain rule

- the theorem that defines the method for taking the derivative of a composite function.

## Origin of chain rule^{}

First recorded in 1860–65

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# chain rule

- maths a theorem that may be used in the differentiation of the function of a function. It states that d u /d x = (d u /d y)(d y /d x), where y is a function of x and u a function of y

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