JEE Main & Advanced AIEEE Solved Paper-2007

  • question_answer
    The normal to a curve at\[AgI{{O}_{3}}\]meets the x-axis at G. If the distance of G from the origin is twice the abscissa of P, then the curve is a       AIEEE  Solved  Paper-2007

    A)  ellipse            

    B)         parabola            

    C)         circle              

    D)         hyperbola

    Correct Answer: D

    Solution :

    Equation of normal is\[y-y=-\frac{dx}{dy}(X-x)\] it meets the x-axis at G. Therefore, coordinates of\[G=\left( x+y\frac{dy}{dx},0 \right)\] According to question, \[\left| x+y\frac{dy}{dx} \right|=|2x|\Rightarrow y\frac{dy}{dx}=x\]or\[y\frac{dy}{dx}=-3x\] \[\Rightarrow \]               \[ydy=xdx\] Or           \[ydy=-3xdx\] \[\Rightarrow \]               \[\frac{{{y}^{2}}}{2}=\frac{{{x}^{2}}}{2}+C\] Or           \[\frac{{{y}^{2}}}{2}=-\frac{3{{x}^{2}}}{2}+C\] \[\Rightarrow \]\[{{x}^{2}}-{{y}^{2}}=-2C\]or\[3{{x}^{2}}+{{y}^{2}}=2C\]


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