Respuesta :

[tex]\dfrac\partial{\partial y}\left[e^{2y}-y\cos xy\right]=2e^{2y}-\cos xy+xy\sin xy[/tex]

[tex]\dfrac\partial{\partial x}\left[2xe^{2y}-y\cos xy+2y\right]=2e^{2y}+y\sin xy[/tex]

The partial derivatives are not equal, so the equation is not exact.