wikipedia:jp:余弦定理 wikipedia:en:Law_of_cosines http://doc.pisan-dub.jp/2010/20100728001/3_3.html#3.3.3.2

wikipedia:jp:決定論 wikipedia:en:Determinism http://plato.stanford.edu/entries/determinism-causal/ http://philsci-archive.pitt.edu/view/subjects/determinism-indeterminism.html