Für das Kreuzprodukt dreidimensionaler Vektoren gilt:
a → × ( b → × c → ) = b → ( a → ⋅ c → ) − c → ( a → ⋅ b → ) {\displaystyle {\vec {a}}\times ({\vec {b}}\times {\vec {c}})={\vec {b}}({\vec {a}}\cdot {\vec {c}})-{\vec {c}}({\vec {a}}\cdot {\vec {b}})} .
