Please explain too In Exercises $1-6,$ verify Green's theorem for the given vector field

$F=M(x,y)i+N(x,y)j$

and region $D$ by calculating both

$o{\displaystyle \underset{\text{d}\text{e}\text{l}\text{D}}{\overset{\phantom{}}{}}}Mdx+Ndy,$ and $,{}_D(N_x-M_y)dA.$

$F=-x^{2}yi+x{y}^{2}j,D$ is the disk

$x^2+y^{2}4$