Electrostatics

Five charges, '\(q\)' each are placed at the comers of a regular pentagon of side '\(a\)' as shown in figure. First, charge from '\(A\)' is removed with other charges intact, then charge at '\(A\)' is replaced with an equal opposite charge. The ratio of magnitudes of electric fields at \(\mathrm{O}\), without charge at \(A\) and that with equal and opposite charge at \(A\) is