How to differentiate using the chain rule
The chain rule evaluates the derivative of a composite function as . It applies whenever a differentiable function is nested inside another differentiable function.
The setup
Identify the composition. Define the inner function as and the outer function as .
The steps
- Find the derivative of the outer function with respect to , yielding .
- Find the derivative of the inner function with respect to , yielding .
- Multiply these two derivatives to get .
- Substitute the original expression for back into .
Checking the result
If the function can be expanded algebraically (e.g., a low-power binomial), do so and differentiate term-by-term using the power rule to verify your result matches.
Common errors
The most frequent error is differentiating the outer function but forgetting to multiply by the derivative of the inner function. Another common mistake is differentiating the inner function inside the argument of the outer function, rather than evaluating the outer derivative at the original inner function.
Worked example
Evaluate the derivative of with respect to .
Let and .
Find the derivative of the outer function: .
Find the derivative of the inner function: .
Multiply the derivatives: .
Substitute back: .
FAQ
Run your own problem
References: Calculus, Volume 1 (OpenStax) · Calculus: Early Transcendentals (Stewart) · AP Calculus AB (Khan Academy)
See also