%
% tkz-euclide (14/01/2011)
%
% Coding (utf8) Creator (TeX) Producer (pdfeTeX) 
% Author Alain Matthes
\input{tkzfctpreamble.ltx}

\begin{document}

\begin{tikzpicture}[scale=.8]
 \tkzInit[xmin=5,xmax=40,ymin=0,ymax=350,xstep=2.5,ystep=25]
 \tkzAxeX[label=$q$]
 \tkzAxeY[label=$C(q)$] \tkzGrid
 \tkzFct[domain=5:40]{0.1*\x**2+2*\x+60}
 \foreach \vv in {5,10,...,40}{%
   \tkzDefPointByFct(\vv)
    \tkzDrawPoint(tkzPointResult)}
 \tkzFct[domain=5:40]{(108*log(\x)-158)}
 \tkzText(37.5,280){$C$}
 \tkzText(37.5,220){$R$}
 \tkzDefSetOfPoints{%
 5/15,10/90,15/135,20/170,25/190,30/200,35/230,40/240}
\tkzDrawSetOfPoints[mark = x,mark size=3pt]
\end{tikzpicture}

\end{document} 
