Given a uniformly charged plane/sheet of surface charge density

Given a uniformly charged plane/sheet of surface charge density
(i) Find the electric field intensity at a point A, 5 mm away from the sheet on the left side.
(ii) Given a straight line with three points X, Y & Z placed 50 cm away from the charged sheet on the
right side. At which of these points, the field due ‘ to the sheet remain the same as that of point A and
why ?

(ii) At point Y. Because at 50 cm, the charge sheet acts as a finite sheet and thus the magnitude remains same towards the middle region of the plane sheet

I am facing difficulty in solving 2d part please help