Author(s):
Daniel Gries (Hopkins School)
Draw your own function on the upper axes by clicking on the screen and dragging the mouse to set y-coordinates of points to be smoothly connected. The applet will show (on the lower axes) the antiderivative function resulting from the definite integral from a to x of your function. Since the points a and x are draggable (on both sets of axes), there are a wide range of explorations possible. Note that to emphasize the "antiderivative connection", the user has the option to show a tangent line at x on the lower graph to see directly the connection between its slope and the values of the upper function.
This applet requires the free Flash Player 9 browser plug-in available from Adobe.

Open the Integral Sketch applet in a separate window
Daniel Gries (Hopkins School), "Area from Hand-Drawn Functions," Convergence (February 2010), DOI:10.4169/loci002640