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In page Chain rule:

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The chain rule can be applied to composites of more than two functions. To take the derivative of a composite of more than two functions, notice that the composite of f, g, and h (in that order) is the composite of f with gh. The chain rule states that to compute the derivative of fgh, it is sufficient to compute the derivative of f and the derivative of gh. The derivative of f can be calculated directly, and the derivative of gh can be calculated by applying the chain rule again.[citation needed]