Please note, some of the derivatives are the same, so some of the graphs
overlap.
Since the constant term doesn't effect
the outcome of a derivative we have a problem here that four of the graphs
are overlaying on top of the four we see. Now it does make since
that the each of a group of four graphs has the same zero since that means
it has the same change in slope from negative to positive. In terms
of a quadratic we usually thing of that value as negative b divided by
two a. As it tells you what the vertex is since that is when the
slope (derivative) changes from positive to negative or vice versa.
