CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2011

  • question_answer
    The focus of the parabola\[{{y}^{2}}+6x-2y+13=0\] is at the point

    A)  \[\left( \frac{7}{2},1 \right)\]                    

    B)  \[\left( \frac{-1}{2},1 \right)\]

    C)  \[\left( -2,\frac{1}{2} \right)\]   

    D)         \[\left( -\frac{7}{2},1 \right)\]

    E)  \[\left( -\frac{1}{2},-1 \right)\]

    Correct Answer: D

    Solution :

    Given, \[{{y}^{2}}+6x-2y+13=0\] \[({{y}^{2}}-2y+1)=-6x-12\] \[{{(y-1)}^{2}}=-6(x+2)\] Let          \[y=y-1\] and         \[X=x+2\] then,       \[{{Y}^{2}}=-6X\]                         ...(i) Which is equation of parabola whose vertex is\[(1,-2)\]and\[\left( a=\frac{3}{2} \right)\] Now, focus  \[=(-a-2,1)\]                                 \[=\left( \frac{-3}{2}-2,1 \right)\]                                 \[=\left( -\frac{7}{2},1 \right)\]


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