Chain Rule

Reference > Calculus: Differentiation

Description
dydx=dydu×dudx\frac{dy}{dx}=\frac{dy}{du}\times \frac{du}{dx}
Examples
ddxsin(lnx)\frac{d}{dx} \sin{(\ln{x})}
1
Use Chain Rule on ddxsin(lnx)\frac{d}{dx} \sin{(\ln{x})}. Let u=lnxu=\ln{x}. Use Trigonometric Differentiation: the derivative of sinu\sin{u} is cosu\cos{u}.
cos(lnx)(ddxlnx)\cos{(\ln{x})}(\frac{d}{dx} \ln{x})

2
The derivative of lnx\ln{x} is 1x\frac{1}{x}.
cos(lnx)x\frac{\cos{(\ln{x})}}{x}

Done

See Also