Consider the function $\displaystyle f(x) = 2\sin(x) - \frac{1}{2} x^2$ This function has two inflection numbers $A<B$ in $[0,2\pi]$:
$A =$
and $B =$ For each of the following intervals, tell whether $f(x)$ is concave up (type in CU) or concave down (type in CD).
$[0,A)$
$(A,B)$
$(B,2\pi]$