# How do you find the derivative of f (x) = 3x^5 + 4x using the limit definition?

Mar 29, 2018

$f ' \left(x\right) = 15 {x}^{4} + 4$

#### Explanation:

The basic rule is that ${x}^{n}$ becomes $n {x}^{n - 1}$

So $5 \cdot 3 {x}^{5 - 1} + 1 \cdot 4 {x}^{1 - 1}$

Which is
$f ' \left(x\right) = 15 {x}^{4} + 4$