1. differentiation

okay im really struggling with this. how would i differentiate the function

y=1
---
ln (x)

2. I'm guessing you mean

$\frac{d}{dx} \lparen\frac{1}{ln(x)}\rparen$

Do you know how do differentiate $\frac{1}{x}$?

Use the chain rule

$\frac{d}{dx} \lparen\frac{1}{u}\rparen = -\frac{1}{u^2} \frac{du}{dx}$

In this case
$\frac{d}{dx} \lparen\frac{1}{ln(x)}\rparen = -\frac{1}{(ln(x))^2} \frac{d(ln(x))}{dx}$

3. I'm assuming you mean $y = \frac{1}{\ln(x)}$.

You can rewrite this as $y = (\ln(x))^{-1}$ and apply the chain rule

$\frac{dy}{dx} = -(\ln(x))^{-2}\frac{1}{x} = -\frac{(\ln(x))^{-2}}{x} = \frac{1}{x(\ln(x))^{2}}$