Two identical current loops have their centers at (0, 0, 0) and (0, 0, 4) and their

Question:

Two identical current loops have their centers at (0, 0, 0) and (0, 0, 4) and their axes the same as the z-axis (so that the "Helmholtz coil" is formed). If each loop has radius 2 m and carries current 5 A in a^, calculate H at
(a) (0, 0, 0)
(b) (0, 0, 2)