V = 0 at the origin.
Both plane and lines have uniform charge.
Left line: Negative charge density
Right Line: Positive charge density
Radius of lines:a
Distance between lines: L
Distane between lines and plane: D
Find Electric field (El) due to both lines at point P
Find Electric field (Ep) due do plane at point P
E at point P = EP = Ep + El
ΔV(x,y) = -∫EPdy + C
Now solve for C: C = ΔV(0,0) +∫EPdy|(0,0)
C = Q/ΔV
… not sure what to do from here…
Is my approach correct so far?