JEE Main & Advanced Mathematics Conic Sections Question Bank Self Evaluation Test - Conic Sections

  • question_answer
    If the ellipse \[9{{x}^{2}}+16{{y}^{2}}=144\] intercepts the line \[3x+4y=12,\] then what is the length of the chord so formed?

    A) 5 units

    B) 6 units

    C) 8 units

    D) 10 units

    Correct Answer: A

    Solution :

    [a] Here, \[9{{x}^{2}}+16{{y}^{2}}=144\] And \[3x+4y=12\] \[\Rightarrow x=\frac{12-4y}{3}\] So, \[9{{\left( \frac{12-4y}{3} \right)}^{2}}+16{{y}^{2}}=144\] On solving we get, \[y=0,3\] For \[y=0;\,\,x=4\] For \[y=3;\,\,x=0\] \[\Rightarrow \] Length of chord \[=\sqrt{{{(0-3)}^{2}}+{{(4-0)}^{2}}}=\sqrt{9+16}\]  \[=\sqrt{25}=5\,\,units\]


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