Consider vectors
and . Note that the right – hand side is the expansion of a third – order determinant along the row with elements and . Thus, the coordinates of the vector product are determined form the third – order determinant as , (9) and its absolute value is
. Example 1. Given the vectors and , find the vector products (а) ; (b) (а) Let us use the expression (9) a vector product: . (b) Let us find the required product by using associativity:
= , = . Since the second product is expressed linearly in terms of the first, it sufficed to multiply the coordinates of the first vector by 4: , whence .
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