yes ur guess is right the equation u wrote is the one I meant . yet I didnt reach any thing that make sense. I guess because I don't know the charge density for the point charge and because I don't know a lot about dirac delta function. I know it converts continuous functions into discreete...
I want to prove coulomb's low for a single charge point from the general form of coulomb's low:
E→=1/(4∏€) ∫∫∫ ρv(ŕ) * (r→- ŕ→)/│(r→- ŕ→)│^3 dŕ
using Dirac Delta function
where r→ is the field point vector
ŕ→ is the source point vector
ρv(ŕ) is the volume charge density
I really don't...