# Natural log derivative problem

Hello all. I am stuck on this homework problem. It wants me to find
$$\frac {d^2y} {dx^2}$$
when $$y= ln x^8$$
The book answer is $$\frac {-8}{x^2}$$
But I only can get $$\frac {-8}{x^9)}$$

Thanks

Last edited:

saltydog
Homework Helper
compute_a_nerd said:
Hello all. I am stuck on this homework problem. It wants me to find
$$\frac {d^2y} {dx^2}$$
when $$y= ln x^8$$
The book answer is $$\frac {-8}{x^2}$$
But I only can get $$\frac {-8}{x^9)}$$

$$y=ln(x^8)$$