Gradient of $y=\ln x$

Gradient of y=\ln x

\frac{dy}{dx} \ln x = \frac{1}{x}

Gradient of y=\log{ax}

So the gradient of y=\log{ax} is \frac{1}{x} as well.

Gradient of y=k\ln x

So the gradient of y=k\ln x is \frac{k}{x}.