Two charges are located on the x-axis: q1 = 5.6 μC at x1 = 4.4 cm, and q2 = 5.6 μC at x2 = -4.4 cm. Two other charges are located on the y-axis: q3 = 2.3 μC at y3 = 4.6 cm, and q4 = -6.8 μC at y4 = 6.7 cm. Find:
a) The magnitude of the net electric field at the origin.
b) The direction of the net electric field at the origin.