If $y=5^{\log x}$ then $\frac{dy}{dx}=$

$\log y=\log x.\left(\log 5\right)$

Differentiation  we respective to $x$

$\frac{1}{y}\frac{dy}{dx}=\log 5.\frac{1}{x}$

$\frac{dy}{dx}=\frac{y}{x}\log 5$