## Calculus (3rd Edition)

$\frac{5}{x}$
$y= \ln (x^{5})$ Put $t= x^{5}$ Then, $y=\ln t$ According to the chain rule, $\frac{dy}{dx}=\frac{dy}{dt}\cdot\frac{dt}{dx}=\frac{1}{t}\times5x^{4}$ $=\frac{5x^{4}}{x^{5}}=\frac{5}{x}$