JCECE Engineering JCECE Engineering Solved Paper-2006

  • question_answer
    The equation of the ellipse whose foci are \[(\pm \,\,2,\,\,0)\]and eccentricity \[\frac{1}{2}\] is:

    A) \[\frac{{{x}^{2}}}{12}+\frac{{{y}^{2}}}{16}=1\]                   

    B) \[\frac{{{x}^{2}}}{16}+\frac{{{y}^{2}}}{12}=1\]

    C) \[\frac{{{x}^{2}}}{16}+\frac{{{y}^{2}}}{8}=1\]                      

    D)  none of these

    Correct Answer: C

    Solution :

    Let the ellipse be\[\frac{{{x}^{2}}}{{{a}^{2}}}+\frac{{{y}^{2}}}{{{b}^{2}}}=1\]. It is given that \[e=\frac{1}{2}\] and\[ae=2\] Therefore,\[a=4\] Now,       \[{{b}^{2}}={{a}^{2}}(1-{{e}^{2}})\]                   \[{{b}^{2}}=12\] Thus, the required ellipse is\[\frac{{{x}^{2}}}{16}+\frac{{{y}^{2}}}{12}=1\]


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