(a) One way to fill in the "missing link" in Fig. 5.48 is to exploit the analogy between the defining equations for A (?? ?? A = 0, V x A = B) and Maxwell's equations for B (?? ?? B = 0. V x B = ?0J). Evidently A depends on B in exactly the same way that B depends on ?0J (to wit: the Biot-Savan law). Use this observation to write down the formula for A in terms of B.?

(b) The electrical analog to your result in (a) is Derive it, by exploiting the appropriate analogy.

V(r) = 1 E(r'). 4 22 dt'.