Consider the function $f(x) = 12 x^5 + 30 x^4 - 160 x^3 + 2$.
$f(x)$ has inflection values at (reading from left to right) $x = D$, $E$, and $F$
where $D$ is
and $E$ is
and $F$ is
For each of the following intervals, tell whether $f(x)$ is concave up (type in CU) or concave down (type in CD).
$(-\infty, D]$:
$[D,E]$:
$[E,F]$:
$[F,\infty)$: