Hello,

I'm supposed to find the derivative of the following.

Using the form , or turning F(x) into F'(x) (Prime).

Anyway, I'm supposed to solve r=2/3 but I'm not sure how I'm supposed to turn this function into F'(x).

I think I'm supposed to do something like

But I'm not sure how I should be applying the exponent when r = 2/3 - or whether I'm on the right track in that case.

Any tips?

Cheers