Select the sign of the coefficients of the parabola shown in the applet.
Given the parabola with equation [math]y=ax^2[/math], for which values of [math]a\in\mathbb{R}[/math] does the vertex coincide with the origin and the graph lies above the [i]x[/i]-axis?
Given the parabolas with equations [math]y=3x^2[/math] and [math]y=6x^2[/math], which one "contains" the other, that is, has a wider opening?
What is the equation of the axis of symmetry of a parabola in canonical form [math]y=ax^2+bx+c[/math]?[br][br]
Write the equation of a parabola that opens downward and has as axis of symmetry the line [math]x=0[/math].