6. three charged particles make up an equilateral triangle of side length a. the two particles at the base have a charge q, and the particle at the apex has a charge 2q. (a) find the field in the center of the triangle (a point equidistant from each vertex), in terms of q and a. (b) when you place a charge {q}' along the baseline, halfway between the two particles with charge q, the electric field in the center of the triangle is zero. what is the value of {q}' ?