Consider the function $f(x) = \frac{1}{12}\ x^{4} + \frac{6}{6}\ x^{3} + \frac{5}{2}\ x^{2} + 3 x + 9$.

$f(x)$ has two inflection points (keep in mind that the Second Derviative is real handy in determining these!) at $x = C$ and $x = D$ with $C \leq D$
where $C$ is
and $D$ is
Finally for each of the following intervals, tell whether $f(x)$ is concave up (type in CU) or concave down (type in CD).
$(-\infty, C]$:
$[C, D]$:
$[D,\infty)$