Hi

Until here it's ok

I don't agree.The general derivate of ln:

So the derivate should be n/x

It doesn't seem correct to me...Let's derivate

I think it looks correct, can it be simplified?

Let's see the derivate of 1/(ln(x^3)). This is a function similar to 1/u(x). But the derivate of such a function is -u'(x)/uČ(x).

Here, u(x)=ln(x^3)

And the derivate of u(x) is not 3xČ but -3/x.

Here is the mistake, try to write it down again