InterviewSolution
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InterviewSolution
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Let `vec(a)=6vec(i)-3vec(j)-6vec(k) and vec(d)=vec(i)+vec(j)+vec(k)."Suppose that" vec(a)=vec(b)+vec(c) "where" vec(b) "is parallel to" vec(d) and vec(c) " si perpendicular to" vec(d). "Then" vec(c) "is-"`A. `5vec(i)-4vec(j)-vec(k)`B. `7vec(i)-2vec(j)-5vec(k)`C. `4vec(i)-5vec(j)+vec(k)`D. `3vec(i)+6vec(j)-9vec(k)` |
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Answer» Correct Answer - B `vec(b)=lamda(hati+hat(j)+hat(k))` `vec(a)=vec(b)+vec(c)` `vec(c)=vec(a)-lamda (hati+hat(j)+hat(k))` `vec(c)=(6hat(i)-3hatj-6hatk)-lamda(hati+hat(j)+hat(k))` `vec(c)(6-lamda)hat(i)+(-3-lamda)hat(j)+(-6-lamda)hat(k)` `vec(c).vec(lamda)=6-lamda-3-lamda-6-lamda=0` `3lamda=3` `lamda=-1` `vec(c)=7hat(i)-2hat(j)-5hat(k)` |
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