2. Solved Papers
  3. J & K CET Engineering

J & K CET Engineering J and K - CET Engineering Solved Paper-2009

  • question_answer
     A, B, C, D, E, F in that order, are the vertices of a regular hexagon with centre origin. If the position vectors of the vertices A and B are respectively, \[4\hat{i}+3\hat{j}-\hat{k}\]and \[-3\hat{i}+\hat{j}+\hat{k},\] then\[\overrightarrow{DE}\] is equal to

    A)  \[7\hat{i}+2\hat{j}-2k\]   

    B)  \[-7\hat{i}-2\hat{j}+\text{ }2\hat{k}\]

    C)  \[3\hat{i}-\hat{j}-\hat{k}\]     

    D)  \[-4\hat{i}-3\hat{j}+2\hat{k}\]

    Correct Answer: A

    Solution :

    Given, \[\overrightarrow{OA}=4\hat{i}+3\hat{j}-\hat{k}\] \[\overrightarrow{OB}=-3\hat{i}+\hat{j}+\hat{k}\] \[\therefore \] \[\overrightarrow{AB}=\overrightarrow{OB}-\overrightarrow{OA}\] \[=-7\hat{i}-2\hat{j}+2\hat{k}\] \[\therefore \] \[\overrightarrow{DE}=-\overrightarrow{AB}=7\hat{i}+2\hat{j}-2\hat{k}\]   


You need to login to perform this action.
You will be redirected in 3 sec spinner