What is the cross product of $[1, - 2, - 1]$ $[1,-2,-1]$ and $[0, - 1, 1]$ $[0, -1, 1]$ ?

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Answer 1 · 2017-10-28T08:23:37

$- 3 ˆ i + ˆ j - ˆ k$ $-3hati+hatj-hatk$

$[1, - 2, - 1] \times [0, - 1, 1]$ $[1,-2,-1]xx[0,-1,1]$

can be calculated by the determinate

$|(hati,hatj,hatk),(1,-2,-1),(0,-1,1)|$

expanding

$hati|(-2,-1),(-1,1)|-hatj|(1,-1),(0,1)|+hatk|(1,-2),(0,-1)|$

$=hati(-2 - 1)+hatj(1-0)+hatk(-1-0)$

$=-3hati+hatj-hatk$

What is the cross product of [1,-2,-1][1,−2,−1][1,-2,-1] and [0, -1, 1] [0,−1,1][0, -1, 1] ?