Exact

$(3x^2+3x{y}^2)dx+(3x^{2}y-3y^2+2y)dy=0$

$(2+y{e}^{xy})dx+(x{e}^{xy}-2y)dy=0$

$(3x^3+3x{y}^2)dx+(3x^{2}y-3y^2+2y)dy=0$

$(yse{c}^{2}x+secxtanx)dx+(tanx+2y)dy=0$

$(cosy-ycosx)dx-(sinx+xsiny)dy=0$

$(2xsinh(\frac{y}{x})+3ycosh(\frac{y}{x}))d-(3xcosh(\frac{y}{x}))d=0$

$dx-(1-x^2)cotyd=0$

$\frac{dy}{dx}-xtan(y-x)=1$