d-c.tex

$$\vcenter {\offinterlineskip
    \def \cc#1{ \hfil #1 \hfil }
    \halign {
    \tvg \cc {$#$}& #\tv & \cc {$#$} & \cc {$#$}& \cc {$#$}&
\cc {$#$}& \cc {$#$} &#\tv\cr
    \noalign {\hrule}
        x&& 0&& 2&& 8&
    \cr
    \noalign {\hrule}
    f'(x)&&& -& 0& +&&
    \cr
    \noalign {\hrule}
    \buuucenter {$f(x)$} &&\bbuup{1} &\bbrightddownarrow & \down {0}
    &\bbrightuuparrow &\bbuup {2}&
    \cr
    \noalign {\hrule}
    }}
$$