SORRY YOU ARE RIGHT , is the same formula but without the epsilon 0.
thats was for part a) , now for calulating the E.F for outisde the sphere i got this:
http://img36.imageshack.us/img36/8785/dddv.png"
for this i don't know how to solve the integration.. please help...!
Homework Statement
Problem : Supose that there is a solid sphere of radius R , with density charge that's depends of the distance to the centre of the sphere ( p = p(r)) :
Question: supose that we know the electric field inside the sphere that is...