This applet may be used as a solver for exact differential equations. As for any solver the best way to use it is to first solve the problem yourself. A DE [math]M\left(x,y\right)dx+N\left(x,y\right)dy=0[/math] if [math]\frac{\partial M}{\partial y}=\frac{\partial N}{\partial x}[/math]. Follow the instructions on the applet. The applet checks the DE for exactness in which case it gives step-wise solution and shows the slope field too.