The following applet can be used to draw "slope fields" for the differential equation y' = f(x,y). Simply enter the function f(x,y) and the values a and b. The applet automatically draws a sample solution through the point (a,b). The values a and b can be changed by simply typing a new value, such as "1.2345", "pi/2", "sqrt(5)+cos(3)", etc. You may also change these values by using the up/down arrow keys or dragging the corresponding point left or right. To move the center of the graph, simply drag any point to a new location. To label the x-axis in radians (i.e. multiples of pi), click on the graph and press "control-r". To switch back, simply press "control-r" again.