The sliders above alter the a, b and c in the equation y=ax2+bx+c
The discriminant, b2+4ac is also shown. Look at what happens to the roots of the equation (x1 and x2) as the discriminant swaps from positive, through zero, to negative.
x=-b/2a is the axis of symmetry.
This page was designed to show the effect of the discriminant on the number of roots, while also giving students an idea of other features of the curve such as the axis of symmetry.