an infinite line of charge with charge density λ1= 4.5 μC/cm is aligned with the y axis (at x=0, stretching infinitely In the y direction). A point P is located at (x,y) = (α,0) where α = 7.2cm. later, another infinite line of charge with charge density λ2 = -13.5 μC/cm is added parallel to the y axis at x = 1/2α = 3.6cm. A cylindrical surface of the radius α and height h = 10.5cm is coaxial with the y axis and centered on the origin (x,y) = (0,0). finally, the initial infinite line of charge is moved so that it is parallel to the y-axis at x = -3.6cm.