newton[z_] := z - f[z]/f'[z]

    plot[r_] :=
     ListDensityPlot[Arg@FixedPoint[newton, #, 50] & /@
       Table[i + j I, {j, -r, r, 2 r/365.}, {i, -r, r, 2 r/365.}],
      ColorFunction -> "Rainbow",
      DataRange -> {{-r, r}, {-r, r}}]

    f[z_] := z^3 - 1; plot[2.0]

[![enter image description here][1]][1]


     f[z_] := z^5 - 1; plot[2.0]

[![enter image description here][2]][2]


  [1]: https://i.sstatic.net/rWBSq.jpg
  [2]: https://i.sstatic.net/I2x2u.jpg