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Let a=hatj-hatk and c=hati-hatj-hatk, the vector b satisfying axxb+c=vec0 and a.b=3, is |
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Answer» `-hati+hatj-2hatk` `RARR a xx (a xx b) + a xx c = 0` `rArr (a.b)a - (a.a) + a xx c = 0` `rArr 3a - 2B +a xx c = 0` `rArr 2b =3a+a xx c` `rArr 2b = 3hatj - 3hatk -2hati - hatj - hatk` `rArr 2b = - hati + 2hatj - 4hatk` `:. b= - hati + hatj - 2hatk` |
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