Question B1. A parabola y = (x-r1)(x-r2) with roots r < 2 is changing in such a way that the distance between the roots is growing at a constant speed of 1 unit per second. When the distance between the roots is 2, what is the rate of change of the y-coordinate of the vertex? Note: The verter of narabola y (xh) + b is the point (hb) a -