Precise electric field derivation for parallel-plate capacitors

Since the 19th century, physicists and mathematicians have tried to find the Electric field due to various objects. However, the electric field inside a parallel-plate capacitor, one of the most used electronic components, hasn't been derived with precision but rather only with approximations. This paper takes into account this problem and tries to address it by the concept of centre of charge. The paper also derives the electric field at a point outside a uniformly charged ring and electric field at a point perpendicular to a random point on a uniformly charged disc in trying to find the Electric field inside a capacitor.