Two charges are located on the x axis: q1 = +5.5 μC at x1 = +5.0 cm, and q2 = +5.5 μC at x2 = −5.0 cm. Two other charges are located on the y axis: q3 = +3.8 μC at y3 = +4.8 cm, and q4 = −9.9 μC at y4 = +6.2 cm. Find (a) the magnitude and (b) the direction of the net electric field at the origin.