A thin, flat, conducting, circular disc of radius R is located in the x-y plane with its

Question:

A thin, flat, conducting, circular disc of radius R is located in the x-y plane with its center at the origin, and is maintained at a fixed potential V. With the information that the charge density on a disc at fixed potential is proportional to (R² ? ?²) ^??, where ? is the distance out from the center of the disc,

(a) Show that for r > R the potential is