The applet for this section draws a slope field for an equation y' = f(x,y). It allows several choices of the function from a pull-down menu, and allows changing the resolution of the grid (also from a pull-down menu).

It instructs the student to drag the mouse to draw a solution curve through the point P. Then the student can click "Check the drawing" to see the exact solution superimposed on the drawing. (The student is scolded if he/she tries to see the solution before attempting drawing.)

Any drawing can be done with multiple drags. This is useful since one often wants to drag to the right starting at P, then drag to the left starting at P. The UNDO button allows the pieces of the curve drawn to be deleted (one at a time in the inverse order that they were drawn).

A mouse click (instead of a drag) will set a new initial point P. (Sometimes if one does a sloppy click it is in fact interpreted as a very short path and appears as a green dot instead of a new point P. Just click again cleanly.)