Chapter 3, Problem 3.26P

Suppose $H=y^2{a}_x+x^2{a}_{y}A/m$ .(a) Calculate $\oint H\cdot dL$ around the path $A\to B\to C\to D\to A$, where $A(2m,0,0)$, $B(2m,4m,0)$, $C(0,4m,0)$, and $D(0,0,0)$ .(b) Divide this $\oint H\cdot dL$ by area $S(2m\times 4m=8m^2)$ .(c) Evaluate $\nabla \times H$ at the center point.(d) Comment on your results for (b) and (c).