Two very large, nonconducting plastic sheets, each 10.0 cm thick, carry uniform charge densities σ1,σ2,σ3 and σ4 on their surfaces, as shown in the following figure(Figure 1). These surface charge densities have the values σ1 = -7.40 μC/m2 , σ2=5.00μC/m2, σ3 = 1.20 μC/m2 , and σ4=4.00μC/m2. Use Gauss's law to find the magnitude and direction of the electric field at the following points, far from the edges of these sheets.