[BlindMath] I need help with vectors and electric field

[Abdulqadir Ahmad]

Hi,

I am a Computer Science student at a university. Part of the courses I 
am taking this semester is physics 102 (electromagnetism) and math 102 
(elementary mathematics II => Functions, vectors and geometry).

Now, we haven't done vectors in math 102 yet, so I don't really 
understand vectors that much.

Here is a question that have been frying my brain cells for days now:
A charge 4 Micro Coulombs is placed 60 cm away from the charge -4 micro 
coulombs. What is the electric field:

1. A point P mid way between the charges.
2. A point Q 40 cm from P and equi-distance between the two charges.
Here is what I know:

1. The formular for calculating electric field: The product of coulombs 
constant and the magnitude of the charge all divided by the square of 
the distance between the point of interest and the charge.

2. How to get the resultant electric field: By calculating the vector 
sum of each electric field.

3. The direction of electric field: It goes from positive to negative 
and points towards the direction a positive charge will experience a 
force when situated in the point.

Another thing I want to note is: the distance from q to both charges is 
50 cm. I got this by moving q upwards 40 cm from p and getting the line 
directly from the point to the charge using pythogoras theorum.

Now, I can get the magnitude of the electric field by substituting the 
values of k, q and r into the electric field formula.

Where I am absolutely confused is how to get the magnitude and direction 
of the resultant electric field at each point. Should I add both 
electric fields? Or subtract? Or do I need trigonometry?

Seeking for help,

Abdulqadir Ahmad