With reference to Fig. 5-10, (a) Derive an expression for

With reference to Fig. 5-10,
(a) Derive an expression for the vector magnetic potential A at a point P located at a distance r from the wire in the x–y plane, and then
(b) Derive B from A. Show that your result is identical with the expression given by Eq. (5.29), which was derived by applying the Biot–Savart law.