I'm a bit confused, if
$\displaystyle y= e^x $
then $\displaystyle x = log_{e}y $
$\displaystyle log_{e} = ln$
$\displaystyle x = log_{e}y = lny $
So why is the natural log always shown as $\displaystyle lnx $ and not $\displaystyle lny ?$
I'm a bit confused, if
$\displaystyle y= e^x $
then $\displaystyle x = log_{e}y $
$\displaystyle log_{e} = ln$
$\displaystyle x = log_{e}y = lny $
So why is the natural log always shown as $\displaystyle lnx $ and not $\displaystyle lny ?$
As MF said you can take the natural log of any pronumeral you wish.
In most textbooks I have seen, a lot of the questions are in the form $\displaystyle y = f(x)$, this means y is equal to a function of x. A lot of natural log questions therefore are along the lines of $\displaystyle y = \ln{x} + somethingelse$.
This will be the reason that the majority of questions you have seen are $\displaystyle \ln{x}$, not $\displaystyle \ln{y}$.