Four equal charges q are sitting on the vertices of an square (imaginary). How many neutral point will be formed inside the plane of the square?

Question

Four  equal charges q are sitting on the vertices of an  square  (imaginary). How many neutral point will be formed inside the plane of the square?

anonymous · Answer

according to Columb's equation $$F=K Q1Q2divR ^{2}$$ each charge will act a force on the other charges. this Force have a Field (E), which have equation $$E=KQ1divR ^{2}$$. that mean the Force Field of each charge depen on the distance. 
 the point inside the plane , where there are neutral this mean the sum of the force Fields = Zero $$\sum_{?}^{?} E=Zero$$
according to Force Field equation $$K Q divR _{1} ^{2} +K Q divR _{2} ^{2}+K Q divR _{3} ^{2}+K Q divR _{4} ^{2}=Zero$$
after Maths we will find the answer id 
 only one point in the center of the square where vectors opposite and equal