Implicit differentiation extends the chain rule to equations not explicitly solved for y, enabling differentiation of curves like circles and ellipses. Inverse function differentiation provides systematic formulas for derivatives of inverse trigonometric, exponential, and logarithmic functions. Together with the chain rule for composite functions and higher-order derivatives, these techniques form the core of AP Calculus AB Unit 3: Differentiation of Composite, Implicit, and Inverse Functions.
The chain rule is the gateway to differentiating composite functions. When equations relate x and y implicitly (like $x^2 + y^2 = 25$), implicit differentiation treats y as a function of x and applies the chain rule to every y-term. Inverse function derivatives extend this further.
Higher-order derivatives reveal concavity, inflection points, and acceleration. Second derivatives found via implicit differentiation often require substituting the first derivative back into the expression.