Copy of Quadratic equations and parabolas - 3 (complete vertex form)

This applet allows you to move the vertex of a parabola (using the sliders), and change the direction and width of the parabola.
How does the parameter 'a' influence the shape of the parabola?[br]How does the parameter 'a' influence the equation of the parabola?
– Robelle Nidoy, wolfteach

Information: Copy of Quadratic equations and parabolas - 3 (complete vertex form)