InterviewSolution
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InterviewSolution
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If `P=(0,1,0) and Q=(0,0,1)` then the projection of `PQ` on the plane `x+y+z=3` isA. 2B. 3C. `sqrt(2)`D. `sqrt(3)` |
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Answer» Correct Answer - C The projection of `PQ` on the given plane is `PQ cos theta` where `theta` is the angle between `PQ` and the plane. Let `vecn` be a vector normal to the plane. We have `vec(PQ)=-hatj+hatk` and `vecn=hati+hati+hatk` `:.sin theta=(vec(PQ).vecn)/(|vec(PQ)||vecn|)=0impliesvec(PQ)` is parallel to the plane. Hence projection of `vec(PQ)` on the given plane `=|vec(PQ)|cos theta=|vec(PQ)|=sqrt(1+1)=sqrt(2)` |
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