I don't understand

I don't understand eume the core is not ferromagnetic, 6 For circular coil of radius R and N turns carrying CUrrent magnitude of the magnetic field at a point on its axis at a distanc from its centre is given by, golR2N B: 3/2 2 (a) Show that this reduces to the familiar result for field at centre of the coil. (b) Consider two parallel co-axial circular coils of equal radius and number of turns N, carrying equal currents in the direction, and separated by a distance R. Show that the fiel( the axis around the mid-point between the coils is uniform a distance that is small as compared to R, and is given by. B = 0.72 approximately. [Such an arrangement to produee a nearly uniform field over a small region is known a.