如何查找并绘制曲线的最大值

Question

我想找到曲线的最大值并显示如下图所示的值。我在这个论坛中找不到适用于我的情况的任何示例。

\documentclass[border=5pt]{standalone}


\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}
\usepgfplotslibrary{units}



\begin{document}

\begin{tikzpicture}
    \begin{axis}[change y base,
            x unit= ,
            % y SI prefix=kilo, 
            y unit= ,
    xmin=0,   xmax=1,
    ymin=0,   ymax=1.1,
%     ytick={0,1000,...,6000},
      xlabel=Degree,
      ylabel=Force,
      xlabel={$S_r$},
  ylabel={$F_x/F_z$},
  xlabel style={below right},
  ylabel style={above left},
        height=8cm,
        width=9cm,
        grid=minor,
        samples=99,
        trig format plots=rad
    ]
    
\newcommand\SV{80.1}
\newcommand\SH{0}
\newcommand\B{0.210}
\newcommand\C{1.67}
\newcommand\D{6090}
\newcommand\E{0.686}
\newcommand\Fz{6000}
        
\addplot[domain=0:1, blue,  thick]  {(\SV+\D*sin(\C*atan(\B*(1-\E)*(x*100+\SH)
                                                        +( atan(\B*(x*100+\SH)) 
                                                            )  
                                                        )
                                                )
                                                )/\Fz
                                    };
        \addlegendentry{$F_x(F_z=6kN)$}
    \end{axis}

\end{tikzpicture}

\end{document}

Answer 1

在这个帖子我现在已经能够绘制我想要的内容（无需进行导数计算）。

\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}
\usepgfplotslibrary{units}




\makeatletter
\pgfplotsset{
    /tikz/max node/.style={
        anchor=south,
    },
    /tikz/min node/.style={
        anchor=north,
        name=minimum
    },
    mark min/.style={
        point meta rel=per plot,
        visualization depends on={x \as \xvalue},
        scatter/@pre marker code/.code={%
            \ifx\pgfplotspointmeta\pgfplots@metamin
                \def\markopts{}%
                \coordinate (minimum);
                \node [min node] {
                    \pgfmathprintnumber[fixed]{\xvalue},%
                    \pgfmathprintnumber[fixed]{\pgfplotspointmeta}
                };
            \else
                \def\markopts{mark=none}
            \fi
            \expandafter\scope\expandafter[\markopts,every node near coord/.style=green]
        },%
        scatter/@post marker code/.code={%
            \endscope
        },
        scatter,
    },
    mark max/.style={
        point meta rel=per plot,
        visualization depends on={x \as \xvalue},
        scatter/@pre marker code/.code={%
        \ifx\pgfplotspointmeta\pgfplots@metamax
            \def\markopts{}%
            \coordinate (maximum);
            \node [max node] {
                \pgfmathprintnumber[fixed]{\xvalue},%
                \pgfmathprintnumber[fixed]{\pgfplotspointmeta}
            };
        \else
            \def\markopts{mark=none}
        \fi
            \expandafter\scope\expandafter[\markopts]
        },%
        scatter/@post marker code/.code={%
            \endscope
        },
        scatter
    }
}
\makeatother

\begin{document}

\begin{tikzpicture}
    \begin{axis}[change y base,
            x unit= ,
            % y SI prefix=kilo, 
            y unit= ,
    xmin=0,   xmax=1,
    ymin=0,   ymax=1.1,
%     ytick={0,1000,...,6000},
      xlabel=Degree,
      ylabel=Force,
      xlabel={$S_r$},
  ylabel={$F_x/F_z$},
  xlabel style={below right},
  ylabel style={above left},
        height=8cm,
        width=9cm,
        grid=minor,
        samples=199,
        trig format plots=rad,
        domain=0:1, blue,
    axis lines*=middle,after end axis/.code={
        \draw [thick, dashed, gray] (maximum) --({axis cs:0,0}-|maximum);}
    ]
    
\newcommand\SV{80.1}
\newcommand\SH{0}
\newcommand\B{0.210}
\newcommand\C{1.67}
\newcommand\D{6090}
\newcommand\E{0.686}
\newcommand\Fz{6000}
        
\addplot  +[mark max] plot {(\SV+\D*sin(\C*atan(\B*(1-\E)*(x*100+\SH)
                                                        +( atan(\B*(x*100+\SH)) 
                                                            )  
                                                        )
                                                )
                                                )/\Fz
                                    };
        \addlegendentry{$F_x(F_z=6kN)$}
    \end{axis}

\end{tikzpicture}

\end{document}