13. Find the magnitude and direction of the electric field at P due to the two charges shown.
The Attempt at a Solution
I have attached both the question, which involves a diagram, as well as my attempt at the answer below. My first question is regarding direction. Since the charge on point P is not known, how do you know the directions of the other two charges in order to draw the vector diagram if you don't know whether they attract or repel P? Also, the answer given is 1.87 x 10^10 N/C [E 15.5 S] but I get the answer to the power of 22. All help is very much appreciated! Thanks!