E-field of a molecule on a point

[acedeno]

Homework Statement

http://postimage.org/image/cky823nof/

Homework Equations

E=kq/r^2

The Attempt at a Solution

I figured I would just find the electric field produced at point * by each individual charge and then add them. For example if I were to set E1 to be the top molecule the field produced by 2e would be

E1=k2e/(R^2+0.25) where r = √(R^2 + 0.5^2)

so E=k[(q1/r1^2)+(q2/r2^2)+(q3/r3^2)+(q4/r4^2)]

 

[ehild]

The electric field is vector quantity. The contributions of the different point charges have different directions. Take it into account. ehild