JEE Main & Advanced Mathematics Conic Sections Question Bank Ellipse

  • question_answer
    For the ellipse \[25{{x}^{2}}+9{{y}^{2}}-150x-90y+225=0\]the eccentricity \[e=\]              [Karnataka CET 2004]

    A)            2/5 

    B)            3/5

    C)            4/5 

    D)            1/5

    Correct Answer: C

    Solution :

               Given equation of ellipse is,                    \[25{{x}^{2}}+9{{y}^{2}}-150x-90y+225=0\]                    \[\Rightarrow \]\[25\,{{(x-3)}^{2}}+9{{(y-5)}^{2}}=225\]                    \[\Rightarrow \]\[\frac{{{(x-3)}^{2}}}{9}+\frac{{{(y-5)}^{2}}}{25}\] = 1. Here \[b>a\]                    \[\therefore \] Eccentricity\[e=\sqrt{1-\frac{{{a}^{2}}}{{{b}^{2}}}}=\sqrt{1-\frac{9}{25}}\]\[=\sqrt{\frac{16}{25}}=\frac{4}{5}\].


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