Question

A +1.3-nC point charge is placed at one corner of a square (1.1 m on a side), and a -3.1-nC charge is placed on the corner diagonally opposite. What is the magnitude of the electric field at either of the other two corners?

Answer 1

what is cosine 45 * ( k*1.3n/1.1^2 -k*3.1n/1.1^2)