\documentclass[a4paper,10pt]{article}
\usepackage{myXsim}

\title{Loi à densité - }
\tribe{Terminale ES}
\date{Février 2020}

\pagestyle{empty}
\geometry{left=10mm,right=10mm, top=10mm}

\usepackage{pgfplots}
\pgfplotsset{compat=1.7}
\pgfmathdeclarefunction{gauss}{2}{%
      \pgfmathparse{1/(#2*sqrt(2*pi))*exp(-((x-#1)^2)/(2*#2^2))}%
  }

\newcommand{\graphs}{%
    \begin{tabular}{cc}

        X \sim \mathcal{B}(40;0.5) & Y \sim \mathcal{N}(20; 10) \\
        \begin{tikzpicture}[
            declare function={binom(\k,\n,\p)=\n!/(\k!*(\n-\k)!)*\p^\k*(1-\p)^(\n-\k);},
            ]
            \begin{axis}[
                yscale=0.5,
                samples at={0,...,40},
                yticklabel style={
                    /pgf/number format/fixed,
                    /pgf/number format/fixed zerofill,
                    /pgf/number format/precision=2
                },
                enlargelimits=false, clip=false, axis on top,
                ybar=0pt, bar width=1
                ]
                %\addplot [fill=cyan, fill opacity=0.5] {binom(x,40,0.2)}; \addlegendentry{$p=0.2$}
                \addplot [] {binom(x,40,0.5)}; 
            \end{axis}
        \end{tikzpicture}
        &
        \begin{tikzpicture}
            \begin{axis}[
                yscale=0.5,
                no markers, domain=0:40, samples=100,
                yticklabel style={
                    /pgf/number format/fixed,
                    /pgf/number format/fixed zerofill,
                    /pgf/number format/precision=2
                },
                %axis lines*=left, xlabel=$x$, ylabel=$y$,
                %every axis y label/.style={at=(current axis.above origin),anchor=south},
                %every axis x label/.style={at=(current axis.right of origin),anchor=west},
                %height=5cm, width=12cm,
                enlargelimits=false, 
                clip=false, axis on top,
                %grid = major
                ]
                \addplot [very thick,cyan!50!black] {gauss(20,3.16)};
            \end{axis}
    \end{tikzpicture}
    \\
        X \sim \mathcal{B}(40;0.4) & Y \sim \mathcal{N}(...; ...) \\
        \begin{tikzpicture}[
            declare function={binom(\k,\n,\p)=\n!/(\k!*(\n-\k)!)*\p^\k*(1-\p)^(\n-\k);},
            ]
            \begin{axis}[
                yscale=0.5,
                samples at={0,...,40},
                yticklabel style={
                    /pgf/number format/fixed,
                    /pgf/number format/fixed zerofill,
                    /pgf/number format/precision=2
                },
                enlargelimits=false, clip=false, axis on top,
                ybar=0pt, bar width=1
                ]
                %\addplot [fill=cyan, fill opacity=0.5] {binom(x,40,0.2)}; \addlegendentry{$p=0.2$}
                \addplot [] {binom(x,40,0.4)}; 
            \end{axis}
        \end{tikzpicture}
        &
        \begin{tikzpicture}
            \begin{axis}[
                yscale=0.5,
                no markers, domain=0:40, samples=100,
                yticklabel style={
                    /pgf/number format/fixed,
                    /pgf/number format/fixed zerofill,
                    /pgf/number format/precision=2
                },
                %axis lines*=left, xlabel=$x$, ylabel=$y$,
                %every axis y label/.style={at=(current axis.above origin),anchor=south},
                %every axis x label/.style={at=(current axis.right of origin),anchor=west},
                %height=5cm, width=12cm,
                enlargelimits=false, 
                clip=false, axis on top,
                %grid = major
                ]
                \addplot [very thick,cyan!50!black] {gauss(16,3)};
            \end{axis}
        \end{tikzpicture}

    \end{tabular}

}

\begin{document}

\graphs
\vfill
\graphs
\vfill
\graphs
\vfill

\end{document}