JEE Main & Advanced Sample Paper JEE Main - Mock Test - 36

  • question_answer
    The equation of the chord of the hyperbola  that is bisected at point (5, 3) is:

    A)          

    B)

    C)             

    D) None of these

    Correct Answer: B

    Solution :

    The equation of the chord, having mid-point as \[\left( {{\operatorname{x}}^{2}},\,\,{{y}^{2}} \right)\] of the hyperbola \[\frac{{{x}^{2}}}{{{a}^{2}}}-\frac{{{y}^{2}}}{{{b}^{2}}}=1\] is given by \[T={{S}_{1}}\]                                                ?. (i) where, \[T=\frac{x{{x}_{1}}}{{{a}^{2}}}-\frac{y{{y}_{1}}}{{{b}^{2}}}-1\,\,and\,\,{{S}_{1}}=\frac{x_{1}^{2}}{{{a}^{2}}}-\frac{y_{1}^{2}}{{{b}^{2}}}-1\] According to the question, \[({{x}_{1}},\,\,{{y}_{1}})=(5,\,\,3)\,\,and\,\,{{a}^{2}}=16,\,\,{{b}^{2}}=25\] as \[25{{x}^{2}}-16{{y}^{2}}=400\] \[\Rightarrow \,\,\,\frac{{{x}^{2}}}{16}-\frac{{{y}^{2}}}{25}=1\] \[\therefore \,\,\,\,\frac{5x}{16}-\frac{3y}{25}=\frac{25}{16}-\frac{9}{25}\]                              [Using (i)] \[\Rightarrow \,\,\,\,125x -48y=625 -144\] \[\Rightarrow \,\,\,125x-48y=481\]


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