Slide 15 of 42
You can do the same for the second derivative, projecting it this
way to get back the plot of f(x), and or this way, to get back the
plot of f''(x), which we also saw before here. And again, you
can project it this way, along the position axis, so we're really
casting out all the position information, to get this parametric
plot of f'' versus f.
