KVPY Sample Paper KVPY Stream-SX Model Paper-29

  • question_answer
    The plane which bisects the line segment joining the points \[(-3,-3,4)\] and \[(3,7,6)\] at right angles, passes through which one of the following points?

    A)  \[(-2,3,5)\]

    B) \[(4,-1,7)\]

    C)  \[(2,1,3)\]

    D) \[(4,1,-2)\]

    Correct Answer: D

    Solution :

    \[A(-3,3,4),(3,7,6)\]
    \[Mid\text{ }point\Rightarrow (0,2,5)\]
    \[\overrightarrow{n}=\overrightarrow{AB}=6\hat{i}+10\hat{j}+2\hat{k}\]
    Equation of plane \[\overrightarrow{r}.\overrightarrow{n}=\overrightarrow{a}.\overrightarrow{n}\]
    \[\overrightarrow{r}.(6i+10\hat{j}+2\hat{k})=(0i+2\hat{j}+5\hat{k}).(6\hat{i}+10\hat{j}+2\hat{k})\]
    \[3x+5y+z=15\]
    \[(4,1,-2)\]satisfies it
    \[\therefore \]Answer is D.


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