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Question
(a) If `veca = hati - 2j + 3veck , vecb = 2hati + 3hatj - 5hatk,` prove that `veca and vecaxxvecb` are perpendicular.
Solution
`bara = hati - 2j + 3k`
`barb = 2hati + 3hatj - 5hatk`
`baraxxbarb=|(hati hatj hatk ),(1 -2 3 ),(2 3 -5)|`
`=hati (10 - 9 ) - hatj (-5 -6)+hatk (3+4)`
`= hati + 11hati + 7hatk`
`bara.(baraxxbarb)=(hati - 2hatj + 3hatk). (hati + 11hatj + 7hatk)`
= 1 - 22 + 21
= - 21 + 21
=0
`bara ⊥ ^r bara xx barb`
`bara` is perpendicular to `bara xx b `
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