¿Cómo conectar dos gráficas con una línea de puntos?

Question

Tengo un problema al conectar dos gráficos con una línea de puntos. La sintaxis de látex se muestra a continuación.

\begin{figure}[h]
\centering
 \begin{subfigure}[b]{0.4\linewidth}
  \begin{tikzpicture}
   \draw[->] (-0.5, 0) -- (4, 0) node[right] {$M$};
   \draw[->] (0, -0.5) -- (0, 4) node [above] {$i$};
   \draw (1.5, 0) -- (1.5, 3.75) node [above] {$M_s$}
   \draw (2.5, 0) -- (2.5, 3.75) node [above] {$M_s'$}
   \draw (0.5, 4) to [bend right =45] (4, 0.5) node[right] {$L$}
  \end{tikzpicture}
  \caption{1} \label{fig:my_label1}
 \end{subfigure}
\begin{subfigure}[b]{0.4\linewidth}
  \begin{tikzpicture}  
      \draw[->] (-0.5,0) -- (4,0) node[right] {$I$};  
      \draw[->] (0,-0.5) -- (0,4) node[above] {$r$};  
      \draw (0.5, 4) to [bend right =45] (4, 0.5) node[right] {$r$}

\end{tikzpicture}
\caption{Interaction} \label{fig:M2}  
\end{subfigure}
\caption{Ravnotežni obseg investicij}
\end{figure} 

Answer 1

¡Bienvenido! Necesita overlayuna rememberimagen para eso, pero probablemente también necesite calcular las intersecciones. El siguiente código hace eso, corrige errores en su código y lo completa en un ejemplo compilable.

\documentclass{article}
\usepackage{subcaption}
\usepackage{tikz}
\usetikzlibrary{intersections}
\begin{document}
\begin{figure}[h] 
\centering 
\begin{subfigure}[b]{0.45\linewidth} 
\begin{tikzpicture}[remember picture] 
\draw[->] (-0.5, 0) -- (4, 0) node[right] {$M$}; 
\draw[->] (0, -0.5) -- (0, 4) node [above] {$i$}; 
\draw[name path=vert1] (1.5, 0) -- (1.5, 3.75) node [above] {$M_s$};
\draw (2.5, 0) -- (2.5, 3.75) node [above] {$M_s'$};
\draw[name path=curve1] (0.5, 4) to [bend right=45] (4, 0.5) node[right] {$L$}; 
\path[name intersections={of=vert1 and curve1,by=i1}] (0,0) coordinate (O1);
\end{tikzpicture} 
\caption{1} 
\label{fig:my_label1} 
\end{subfigure}\qquad 
\begin{subfigure}[b]{0.45\linewidth} 
\begin{tikzpicture}[remember picture]
\draw[->] (-0.5,0) -- (4,0) node[right] {$I$} coordinate (x2);
\draw[->] (0,-0.5) -- (0,4) node[above] {$r$};
\draw[name path=curve2] (0.5, 4) to [bend right =45] (4, 0.5) node[right] {$r$};
\path[overlay,name path=hori] (O1|-i1) -- (x2|-i1);
\draw[name intersections={of=hori and curve2,by=i2},overlay,densely dotted]
 (O1|-i1) --(i2); 
\end{tikzpicture} 
\caption{Interaction}
\label{fig:M2}
\end{subfigure}
\caption{Ravnotezni obseg investicij.}
\end{figure}
\end{document}