# What does it mean to differentiate a function?

$\frac{d}{\mathrm{dx}} f \left(x\right) \mathmr{and} f ' \left(x\right)$.
$\frac{d}{\mathrm{dx}} f \left(x\right) = {\lim}_{h \rightarrow 0} \frac{f \left(x + h\right) - f \left(x\right)}{h}$