JEE Main & Advanced AIEEE Solved Paper-2005

  • question_answer
    Let P be the point (1, 0) and Q be a point on the locus\[{{y}^{2}}=8x.\]The locus of mid-point of PQ is     AIEEE  Solved  Paper-2005

    A) \[{{x}^{2}}-4y+2=0\] 

    B)        \[{{x}^{2}}+4y+2=0\]

    C)        \[{{y}^{2}}+4x+2=0\]   

    D)        \[{{y}^{2}}-4x+2=0\]

    Correct Answer: D

    Solution :

    The coordinates of P are (1, 0). A general point Q on \[{{y}^{2}}=8x\] is\[(2{{t}^{2}},4t)\]. Mid-point of PO is (h, k) so \[2h=2{{t}^{2}}+1\]                           ?.(i) and        \[2k=4t\Rightarrow t=k/2\]                       ...(ii) On putting the value of t from Eq. (ii) in Eq, (i), we get \[2h=\frac{2{{k}^{2}}}{4}+1\Rightarrow 4h={{k}^{2}}+2\] Hence, the locus of (h, k) is\[{{y}^{2}}-4x+2=0.\]


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