# How do I find the derivative of a function at a given point?

$f \left(x\right) = {x}^{3}$
$f ' \left(x\right) = 3 {x}^{2}$
Then if we want to find the derivative of $f \left(x\right)$ when $x = 4$ then we substitute that value into $f ' \left(x\right)$.
$f ' \left(4\right) = 3 {\left(4\right)}^{2} = 3 \cdot 16 = 48$