JEE Main & Advanced Sample Paper JEE Main Sample Paper-11

  • question_answer
    The equation (5x -1)2 + (5y - 2)2 = \[({{\lambda }^{2}}-4\lambda +4)\] (3x + 4y - 1)2 represents an ellipse if\[\lambda \in \]

    A)  (0, 1]                    

    B)  (-1, 2)

    C)  (2, 3)                    

    D)  (-1, 0)

    Correct Answer: C

    Solution :

     \[{{\left( x-\frac{1}{5} \right)}^{2}}+{{\left( y-\frac{2}{5} \right)}^{2}}=({{\lambda }^{2}}-4\lambda +4){{\left( \frac{3x+4y-1}{5} \right)}^{2}}\]i.e., \[\sqrt{{{\left( x-\frac{1}{5} \right)}^{2}}+{{\left( y-\frac{2}{5} \right)}^{2}}}=|\lambda -2|\left| \frac{3x+4y-1}{\sqrt{5}} \right|\] Is an ellipse, if\[<|\lambda -2|<1\]i.e., \[\lambda \in (1,2)\cup (2,3)\]


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