$3\mathrm{.}17$ A cube is defined by D$=2$x$^(2)$ya$\_($x$)+3$x$^(2)$y$^(2)$a$\_($y$)($C$)/($m$^(2))$grad$*$D$1.$ If D$=2$x$^(2)$ya$\_($x$)+3$x$^(2)$y$^(2)$a$\_($y$)($C$)/($m$^(2))$

$($a$)$ Apply Gauss's law to find the total flux leaving the closed surface of the

cube. $($b$)$ Evaluate grad$*$D at the center of the cube. $($c$)$ Use the result from part b to find the total charge enclosed by the cube and compare to part a