# Implicit differentiation

I am currently working on a question which involves me differentiating $$\frac{y}{x}$$

I can't find nothing in books or on the internet about how to deal with this kind of implicit differentiation.

The quotient rule is an equally valid way of going about differentiating your expression. If $u$ and $v$ are functions of $x$, then $$\dfrac{\text{d}}{\text{d}x} \left( \dfrac{u}{v} \right) = \dfrac{vu'-uv'}{v^2}$$ Let $u=y(x)$ and $v=x$ and your result should fall out rather nicely. ^_^
Use the product rule $(fg)' = f'g + fg'$.
$$\frac{d}{dx}\Big(\frac{y}{x}\Big) = \frac{y'}{x} - \frac{y}{x^2}$$