Electric Field of Nonconducting Rod

Question

http://crab.rutgers.edu/~gurfink/physics2/practice_exams/node1.html

Need help with problem 1(c) >> "In the asymptotic limit..."

I believe it's asking to determine the E field as 'a' approaches inifinity.

[1(b) >> E(a)=kq(1/a(L a)]

Answer 1

when you get really far away from it such that the distance from you to the close end of the rod and the distance from you to the far end of the rod are basically the same it seems to me like it would just look like a point charge of charge Q