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In this video I show two interesting formulas involving the dot and cross products in which a vector is used twice. The first equation states the scalar triple product is equal to zero if the same vector occurs twice. The second formula states that adding two vectors and then taking the cross product with one of the added vectors involves one term canceling out because a vector cross product with itself is equal to zero. Interesting stuff!
Timestamps
Question 13: Scalar Triple Triple Product with the same vector twice is zero: 0:12
Proof by evaluating the scalar triple product: 1:50
Question 14: Addition of vectors than cross product with same vector twice: 5:59
Expanding the formula obtain zero: 8:06
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