Area Bounded by 4 Curves

Here is an example using pgfplots and its fillbetween libary.

\documentclass[border=2mm]{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=1.13}
\usepgfplotslibrary{fillbetween}

\begin{document}

    \begin{tikzpicture}
      \begin{axis}[
        set layers,
        axis lines=middle,
        xmin=-3.1,xmax=3,xtickmax=2.9,
        ymin=-3.1,ymax=3,ytickmax=2.9,
        samples=100
      ]
        \addplot[name path=A+,brown, domain=2:3] {sqrt(x^2-4)};
        \addplot[brown, domain=2:3] {-sqrt(x^2-4)};
        \addplot[brown,domain=-3:-2] {sqrt((x)^2-4)};
        \addplot[name path=A-,brown,domain=-3:-2] {-sqrt((x)^2-4)};
        \addplot[name path=B+,green,domain=1:3] {sqrt(x^2-1)};
        \addplot[green,domain=1:3] {-sqrt(x^2-1)};
        \addplot[green,domain=-3:-1] {sqrt(x^2-1)};
        \addplot[name path=B-,green,domain=-3:-1] {-sqrt((x)^2-1)};
        \addplot[name path=C+,red,domain=.15:3]{1/x};
        \addplot[name path=C-,red,domain=-3:-.15]{1/x};
        \addplot[name path=D+,blue,domain=.15:3]{2/x};
        \addplot[name path=D-,blue,domain=-3:-.15]{2/x};

        \path[%draw,line width=3,orange,
          name path=AC+,
          intersection segments={
            of=A+ and C+,
            sequence={L2[reverse] -- R1[reverse]}
          }
        ];
        \path[%draw,line width=3,purple,
          name path=BD+,
          intersection segments={
            of=B+ and D+,
            sequence={L1 -- R2}
          }
        ];

        \path[%draw,line width=3,orange,
          name path=AC-,
          intersection segments={
            of=A- and C-,
            sequence={L1 -- R2}
          }
        ];
        \path[%draw,line width=3,purple,
          name path=BD-,
          intersection segments={
            of=B- and D-,
            sequence={L2[reverse] -- R1[reverse]}
          }
        ];

        \pgfonlayer{axis grid}
          \path [
            fill=orange!30,
            intersection segments={
              of=AC+ and BD+,
              sequence={R2--L2}
            }
          ]--cycle;
          \path [
            fill=orange!30,
            intersection segments={
              of=AC- and BD-,
              sequence={R2--L2}
            }
          ]--cycle;
        \endpgfonlayer

      \end{axis}
    \end{tikzpicture}
\end{document}

enter image description here


Here is an example with only the positive part. Unfortunaly the order and/or the direction of the path segments seems to change if the x- and/or the y-range is changed.

\documentclass[border=2mm]{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=1.13}
\usepgfplotslibrary{fillbetween}

\begin{document}

    \begin{tikzpicture}
      \begin{axis}[
        set layers,
        axis lines=middle,
        xmin=0,xmax=3,xtickmax=2.9,
        ymin=0,ymax=3,ytickmax=2.9,
        domain=.15:3,
        samples=100,
      ]
        \addplot[name path=A,brown, domain=2:3] {sqrt(x^2-4)};
        \addplot[name path=B,green,domain=1:3] {sqrt(x^2-1)};
        \addplot[name path=C,red]{1/x};
        \addplot[name path=D,blue]{2/x};

        \path[%draw,line width=3,orange,
          name path=AandC,
          intersection segments={
            of=A and C,
            sequence={R1 -- L2}
          }
        ];
        \path[%draw,line width=3,purple,
          name path=BandD,
          intersection segments={
            of=B and D,
            sequence={L1 -- R2}
          }
        ];
        \pgfonlayer{axis grid}
          \path [
            fill=orange!30,
            intersection segments={
              of=AandC and BandD,
              sequence={L2[reverse] -- R2}
            }
          ]--cycle;
        \endpgfonlayer

      \end{axis}
    \end{tikzpicture}
\end{document}

Result:

enter image description here


That is not easy, because you have to find first the intersections. And, of course, I suppose you mean only the area in the positive part. The following example works only with latex->dvips->ps2pdf

\documentclass[11pt]{article}
\usepackage{pst-intersect}
\begin{document}

\psset{unit=2}
\begin{pspicture*}(-0.5,-0.5)(3,3)
\psaxes{->}(0,0)(2.75,2.75)[$x$,-90][$y$,90]
\psset{algebraic,plotpoints=51,linewidth=1.5pt}
\pssavepath[linecolor=red!40]{Pa}{\psplot{0.15}{3}{1/x}}%
\pssavepath[linecolor=blue!40]{Pb}{\psplot{0.15}{3}{2/x}}%
\pssavepath[linecolor=green!40]{Pc}{\psplot{0}{3}{(x-1)*(x+1)}}%
\pssavepath[linecolor=yellow]{Pd}{\psplot{0}{3}{(x-2)*(x+2)}}%
\psintersect[name=A]{Pa}{Pc}\psintersect[name=B]{Pa}{Pd}
\psintersect[name=C]{Pb}{Pc}\psintersect[name=D]{Pb}{Pd}
\pscustom[fillcolor=magenta,fillstyle=solid,linestyle=none]{%
  \psplot{\psGetIsectCenter{A}{}{1} I-A1.x}%
         {\psGetIsectCenter{C}{}{1} I-C1.x}{(x-1)*(x+1)}
  \psplot{\psGetIsectCenter{C}{}{1} I-C1.x}%
         {\psGetIsectCenter{D}{}{1} I-D1.x}{2/x}
  \psplot{\psGetIsectCenter{D}{}{1} I-D1.x}%
         {\psGetIsectCenter{B}{}{1} I-B1.x}{(x-2)*(x+2)}
  \psplot{\psGetIsectCenter{B}{}{1} I-B1.x}%
         {\psGetIsectCenter{A}{}{1} I-A1.x}{1/x}
}
\end{pspicture*}

\end{document}

enter image description here

Clipping is also possible, but it is not so easy to understand how the clipping path has to be build. This example works also with xelatex

\documentclass[11pt]{article}
\usepackage{pst-plot}
\begin{document}

\psset{unit=2}
\begin{pspicture}(-3,-3)(3,3)
\psaxes{->}(0,0)(-3,-3)(2.75,2.75)[$x$,-90][$y$,0]
\psset{algebraic,plotpoints=51}
\psclip[linestyle=none]{%
  \pscustom{\psplot{1}{3}{1/x}\lineto(3,3)}
  \pscustom{\psplot{2}{1}{sqrt(x^2-1)}\lineto(4,1)}
  \pscustom{\psplot{2}{2.5}{sqrt(x^2-4)}\lineto(-1,3)}  
  \pscustom{\psplot{2.5}{1}{2/x}\lineto(1,-1)}  
}
  \psframe*[linecolor=magenta,opacity=0.3](3,3)
\endpsclip
\psplot[linecolor=red]{0.7}{3}{1/x}%
\psplot[linecolor=green]{2}{1}{sqrt(x^2-1)}%
\psplot[linecolor=yellow]{2}{2.5}{sqrt(x^2-4)}%
\psplot[linecolor=blue]{2.5}{1}{2/x}%
\psclip[linestyle=none]{%
    \pscustom{\psplot{-1}{-3}{1/x}\lineto(-3,-3)}
    \pscustom{\psplot{-2}{-1}{-sqrt(x^2-1)}\lineto(-4,-1)}
    \pscustom{\psplot{-2}{-2.5}{-sqrt(x^2-4)}\lineto(1,-3)} 
    \pscustom{\psplot{-2.5}{-1}{2/x}\lineto(-1,1)}  
}
\psframe*[linecolor=magenta,opacity=0.3](-3,-3)
\endpsclip
\psplot[linecolor=red]{-0.7}{-3}{1/x}%
\psplot[linecolor=green]{-2}{-1}{-sqrt(x^2-1)}%
\psplot[linecolor=yellow]{-2}{-2.5}{-sqrt(x^2-4)}%
\psplot[linecolor=blue]{-2.5}{-1}{2/x}%
\end{pspicture}

\end{document}

enter image description here

For the clipping path: If one curve ends then the next one starts with a straight line between these two curves. This is the reason why I choose the '\lineto` macro which moves my current point to a place where a follwing straight line to the next curve doesn't go through the clipped area. That's all.