What if we wanted to figure out whether the vertex of the function is a minimum value or a maximum value? We would need to look at the value of
a in the vertex form.
y=a(x−h)2+k⇒y=-1(x−2)2+3
Because
a=-1 is negative, we know that the parabola opens down and the
y-coordinate of the vertex,
3, is the
maximum value. Let's graph our function to confirm this conclusion!