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If `veca=hati-2hatj+3hatk, vecb=2hati+3hatj-hatk` and `vecc=rhati+hatj+(2r-1)hatk` are three vectors such that `vecc` is parallel to the plane of `veca` and `vecb` then`r` is equal to,A. `1`B. `0`C. `2`D. `-1` |
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Answer» Correct Answer - B It is given `vecc` is parallel to the plane of `veca` and `vecb` `:.vecc_|_vecaxxvecb` `impliesvecc(vecaxxvecb)=0implies[(veca, vecb, vecc)]=0` `implies|(1,-2,3),(2,3,-1),(4,1,2r-1)|=0` `implies(6r-2)+2(5r-2)+(6-9r)=0implies7r=0impliesr=0`. |
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