Going one step further and connecting the third graph to the first with points of inflection would have been a good thing to do as well. Other than that this is a great explanation of how to find graphs with derivatives!
Again, the point of inflection has been ignored. This is the point where the gradient stops increasing and starts decreasing. On the graph of the derivative (the parabola) it is the maximum point, which is half way between the roots. On the schetched function, Eddie has drawn it much too close to the second turning point.
