【005_ケプラー予想】コマ大数学科

最密度充填問題，パッキングの問題

直径5cmの缶は縦10cm，横502.5cmの枠に何本入るか。

\begin{tikzpicture}
  % ==階段，放物線，
  % 線を引く
  \\
  \draw [very thick] (0,0) coordinate (O) rectangle (15,2) coordinate (B);
  \coordinate (A) at (15,0);
  \coordinate (C) at (0,2);
  \draw [very thick] (14.5,2.5) coordinate (O1) circle (0.5);
  \draw [dashed](0.5,0.5) circle (0.5);
  \draw [dashed](1.5,0.5) circle (0.5);
  \draw (0,0) rectangle (0.2,0.2);
  \draw (0,1.8) rectangle (0.2,2);
  \draw (14.8,0) rectangle (15,0.2);
  \draw (14.8,1.8) rectangle (15,2);
  \draw (A).. controls ($(A)!.2!(B)!10pt!270:(B)$) and ($(A)!.8!(B)!10pt!270:(B)$) .. (B) node [midway, sloped, fill=white] {$10$cm};
  \draw (O).. controls ($(O)!.2!(A)!15pt!270:(A)$) and ($(O)!.8!(A)!15pt!270:(A)$) .. (A) node [midway, sloped, fill=white] {$502.5$cm};

\end{tikzpicture}