I guess I am unsure why I have the ##g_al## in the log of my final answer when it is not in (**). Because it is there leads me to think that I have not set up the integral correctly by the way I compute the resistance of a typical disc in (i).
So I guess I don't understand how to set up the...
(i) Dividing the rod into thicknesses of dx we get discs of area A with lengths=dx so using (****) we have the resistance of a typical disc (between point x' and x'+dx) as:
(1) ##R(x'dx)=\frac{dx}{g(x)A}##
(ii) Using (1) and (*) and the integrating from a to b of the entire rod we get...