\documentclass[tikz]{standalone}

\begin{document}
\begin{tikzpicture}[scale=2]
\draw[->] 
  (0,0) -- (3,0);
\draw[->] 
  (0,0) -- (0,3);
\draw[] 
   (3,0) node   [right] {$x$};
\draw[] 
   (0,3) node   [left] {$u$};
\draw[] 
   (0,0) node   [left] {$o$};
\draw[thick] (0,0) to [out=90,in=195] (3,2.5);


\draw[dotted] 
   (0.5,1.3) -- (0.5,0) node [below] {$x_1$};

\draw[dotted] 
   (2.5,2.3) -- (2.5,0) node [below] {$x_2$};

\draw[] 
   (2.5,2.34) -- (0.5,1.28);


\draw[dotted] 
   (2.5,2.34) -- (0,2.34) node [left] {$u(x_2)$};


\draw[dotted] 
   (0.5,1.28) -- (0,1.28) node [left] {$u(x_1)$};


\draw[dotted] 
   (1.5,1.8) -- (1.5,0) node [below] {$E[p]$};


\draw[dotted] 
   (1.5,1.8) -- (0,1.8)  node [left] {$U(p)$};


\draw[dotted] 
   (1.17,1.8) -- (1.17,0) node [below] {$x_p$};


  
\end{tikzpicture}
\end{document}