The sliders for a and b change the equations of the parabolas. The check boxes turn on and off the vertical and horizontal parabolas. Use these tools and the information at the right of the window to complete the companion handout.
The companion handout can be downloaded using the link below. https://docs.google.com/open?id=0B5MwyQkaydKZMWp6M0pMWXhjOGc