Math Help - Natural Derivative

1. Natural Derivative

f(x)= ln(5x^4-x)

2. Originally Posted by av8or91
f(x)= ln(5x^4-x)
Use the chain rule

$\frac{d}{dx}ln[f(x)] = \frac{f'(x)}{f(x)}$

In your case $f(x)=5x^4-x$ which s pretty simple to differentiate

3. Originally Posted by av8or91
f(x)= ln(5x^4-x)
The derivative of $y=\ln(f(x))$ is $y'=\frac{f'(x)}{f(x)}$.

So what do you think?

4. oh ok I see it now I think. So its just the derivative of the top/ original function on the bottom.

20x^3-1
5x^4-x

5. Originally Posted by av8or91
oh ok I see it now I think. So its just the derivative of the top/ original function on the bottom.

20x^3-1
5x^4-x
Aside from the syntax then yes

$\frac{20x^3-1}{5x^4-x}$