带渐近线的 y= 图形模板

Question

所以我想画出图表

y=(3^(x))+(-1)

y=(3^(-x))+3

带标签和细网格

清晰地显示渐近线。清楚地

---

我曾尝试过以下

\documentclass{article}
\usepackage{pgfplots}

\begin{document}

\begin{tikzpicture}
\begin{axis}[
  axis lines=middle,
  clip=false,
  ymin=0,
  xticklabels=\empty,
  yticklabels=\empty,
  legend pos=north west
]
\addplot+[mark=none,samples=200,unbounded coords=jump] {(3^(x))+(-1)};
\legend{$y=\sqrt{x}$}
\draw[fill] (axis cs:4,0) circle [radius=1.5pt] node[below right] {$(4,0)$};
\draw[fill] (axis cs:{4.5,sqrt(4.5)}) circle [radius=1.5pt] node[above left] {$(x,y)$};
\end{axis}
\end{tikzpicture}

\end{document}

但无法生成 +(-1) 部分

Answer 1

你的意思是......之类的吗？

\documentclass[border=2pt]{standalone}
\usepackage{pgfplots}
\begin{document}
    \begin{tikzpicture}
        \begin{axis}[
            legend pos=north west,
            axis lines=middle,
            xmax=5,
            ymin=-2,
            ymax=10,
%            xticklabels=\empty,
%            yticklabels=\empty,
            % add some extra ticks with a different style to show the asymptotes
            extra y ticks={-1,3},
            extra y tick style={
                grid=major,
            },
%            % if you don't need the numbers ...
%            extra y tick labels={},
            no markers,
            samples=200,
        ]
            \addplot {(3^(x))+(-1)};
            \addplot {(3^(-x))+3};

%            % alternatively add some more constant plots where you choose
%            % a custom style for each asymptote
%            \addplot [blue!50,samples=2,forget plot] {-1};
%            \addplot [red!50,samples=2,forget plot] {3};

            \legend{
                $3^x - 1$,
                $3^{-x} + 3$,
            }
        \end{axis}
    \end{tikzpicture}
\end{document}