The problem I have is to differentiate $ y = ln(x^4)$
Using the rule : $$\frac{d[lnf(x)]}{dx}=\frac{f'(x)}{f(x)}$$ My working is: $$\frac{dy}{dx} = \frac{x^4ln(x)}{x^4}$$ $$=ln(x)$$
but the book is giving the answer : $$\frac{4}{x}$$
Please help because I am confused