7.7 Connected rates of change

AQA Edexcel
The chain rule is used for connected rates of change.

If \(y = f(u) \) and \(u = g(x) \), then:

\(\boxed{\dfrac{dy}{dx} = \dfrac{dy}{du} × \dfrac{du}{dx}} \)
Important
Chain rule

\(\dfrac{dy}{dx} = f'\big(g(x)\big)g'(x) \)

\(\dfrac{dy}{dx} = \dfrac{dy}{du} × \dfrac{du}{dx} \)
3