JEE Main & Advanced Mathematics Conic Sections Question Bank Parabola

  • question_answer
    For the above problem, the area of triangle formed by chord of contact and the tangents is given by              [Roorkee 1994]

    A)            8     

    B)            \[8\sqrt{3}\]

    C)            \[8\sqrt{2}\]                             

    D)            None of these

    Correct Answer: C

    Solution :

               Solving above equation with parabola \[{{y}^{2}}=4x,\]we get the points \[P(3+2\sqrt{2},\,2+2\sqrt{2}),\,\,Q(3-2\sqrt{2},2-2\sqrt{2})\].                    \\[P{{Q}^{2}}=32+32=64\]Þ \[PQ=8\]                    Also, if p be perpendicular from (?1,2) on PQ, then area of triangle is \[\frac{1}{2}PQ.\,\,p=\frac{1}{2}.8.\left( \frac{4}{\sqrt{2}} \right)=8\sqrt{2}\].


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