1. Drag the "a" slider to set a point where you'd like to determine the instantaneous velocity.
2. Drag the "b" slider to set a point and have Geogebra calculate the average velocity over the interval [math][a, a+h][/math].
3. As you drag b closer and closer to a, observe what the average velocities approach and then guess the instantaneous velocity at point a.
4. Also observe geometrically what happens to the line that is created.
