JEE Main & Advanced Mathematics Three Dimensional Geometry Question Bank Mock Test - Three Dimensional Geometry

  • question_answer
    Let A (1, 1, 1), B (2, 3, 5) and C (\[-\]1,0, 2) be three points, then equation of a plane parallel to the plane ABC which is at distance 2 is

    A) \[2x-3y+z+2\sqrt{14}=0\]

    B) \[2x-3y+z-\sqrt{14}=0\]

    C) \[2x-3y+z+2=0\]

    D) \[2x-3y+z-2=0\]

    Correct Answer: A

    Solution :

    [a] A (1, 1, 1), B(2, 3, 5), C (-1, 0, 2) direction ratios of AB are <1, 2, 4>. Direction ratios of AC are \[<-\,2,\,\,-1,\text{ }1>.\] Therefore, directions ratios of normal to plane ABC are \[<2,\,-3,\text{ }1>\] As a result, equation of the plane ABC is\[2x-3y+z=0\]. Let the equation of the required plane be \[2x-3y+z=k.\] Then \[\left| \frac{k}{\sqrt{4+9+1}} \right|=2\] Or \[k=\pm 2\sqrt{14}\] Hence, equation of the required plane is \[2x-3y+z+2\sqrt{14}=0\]


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