Two 10-cm-long thin glass rods uniformly charged to + 10;{rm nC} are placed side by side, 4.0 cm apart. What are the electric field strengths E_1, E_2, and E_3 at distances 1.0 cm, 2.0 cm, and 3.0 cm to the right of the rod on the left, along the line connecting the midpoints of the two rods?