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Question
If `vec"a" = hat"i" - 2hat"j" + 3hat"k", vec"b" = 2hat"i" + hat"j" - 2hat"k", vec"c" = 3hat"i" + 2hat"j" + hat"k"`, find `(vec"a" xx vec"b") xx vec"c"`
Solution
`vec"a" xx vec"b" = |(hat"i", hat"j", hat"k"),(1, -2, 3),(2, 1, -2)|`
= `hat"i"(4 - 3) - hat"j"(- 2 - 6) + hat"k"(1 + 4)`
= `hat"i" + 8hat"j" + 5hat"k"`
`vec"a" xx vec"b" xx vec"c" = |(hat"i", hat"j", hat"k"),(1, 8, 5),(3, 2, 1)|`
`hat"i"(8 - 10) - hat"j"(1 - 15) + hat"k"(2 - 24)`
= `- 2hat"i" + 14hat"j" - 22hat"k"`
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